Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

Sample

macrumors member
Original poster
Dec 7, 2015
72
18
Hi to all:), I've read the GPU compatibility list:


…but I'm still not sure on which is the best one for my setup, could anyone please be so kind of helping me out with the upgrade of my old GPU? I currently own a:

Mac Pro 4,1 (flashed to 5,1) 2 x 2.26 GHz Quad-Core Intel Xeon
GPU: NVIDIA GeForce GT 120 512 MB
OS: currenly 10.8.5 but will upgrade to Mojave and beyond once I get the new GPU (will still need to access 10.8.5 though)
display: LG 43UD79 4k

Is really the:
SAPPHIRE Radeon HD 7950 Mac Edition (same as ATI/AMD right?)

my best bet? or is there a GPU that has a chance of being more compatible with future OSs and displays?
Which could be the best possible (and recent) GPU I can purchase considering that:

1) I'm not into gaming or graphic intense work, I work with audio so all I badly need is COMPATIBILITY with most OS X versions from 10.8.5 up to Mojave and Catalina and possibly some future OSs, so I gather NVIDIAs are not an option since no longer being supported by Apple right?

2) I need a DP or a miniDP output

3) Would like to reach 4k at 60Hz when watching movies (but most of the time I work at 1080p)

4) possibly able to show boot screen to switch startup disks, with tweaks if needed

5) has to be HDCP compatible

Thanks for you kind help guys ?
all my best
P
 

tsialex

Contributor
Jun 13, 2016
13,094
13,300
Hi to all:), I've read the GPU compatibility list:


…but I'm still not sure on which is the best one for my setup, could anyone please be so kind of helping me out with the upgrade of my old GPU? I currently own a:

Mac Pro 4,1 (flashed to 5,1) 2 x 2.26 GHz Quad-Core Intel Xeon
GPU: NVIDIA GeForce GT 120 512 MB
OS: currenly 10.8.5 but will upgrade to Mojave and beyond once I get the new GPU (will still need to access 10.8.5 though)
display: LG 43UD79 4k

Is really the:
SAPPHIRE Radeon HD 7950 Mac Edition (same as ATI/AMD right?)

my best bet? or is there a GPU that has a chance of being more compatible with future OSs and displays?
Which could be the best possible (and recent) GPU I can purchase considering that:

1) I'm not into gaming or graphic intense work, I work with audio so all I badly need is COMPATIBILITY with most OS X versions from 10.8.5 up to Mojave and Catalina and possibly some future OSs, so I gather NVIDIAs are not an option since no longer being supported by Apple right?

2) I need a DP or a miniDP output

3) Would like to reach 4k at 60Hz when watching movies (but most of the time I work at 1080p)

4) possibly able to show boot screen to switch startup disks, with tweaks if needed

5) has to be HDCP compatible

Thanks for you kind help guys ?
all my best
P
10.8.5 support limits you to NVIDIA GTX 680/780 model A/Titan Kepler/Quadro K4000/other NVIDIA Kepler GPUs and AMD HD 7950/HD 7970/R9 280xx.

No GPU that supports 10.8.5 have 4k 60Hz, only 30Hz.

No newer GPUs support 10.8.5.

HD 7950/HD 7970/R9 280xx plus GTX 680 are self flashable GPUs to Mac EFI and you will have pre-boot configuration support.
 
Last edited:

Sample

macrumors member
Original poster
Dec 7, 2015
72
18
10.8.5 support limits you to NVIDIA GTX 680/780 model A/Titan Kepler/Quadro K4000/other NVIDIA Kepler GPUs and AMD HD 7950/HD 7970/R9 280xx.

No GPU that supports 10.8.5 have 4k 60Hz, only 30Hz.

No newer GPUs support 10.8.5.

HD 7950/HD 7970/R9 280xx plus GTX 680 are self flashable GPUs to Mac EFI and you will have pre-boot configuration support.

Thank you so much for your quick answer tsialex!:)
Ok so I have narrowed down my choice to the:

Radeon HD 7950 3Gb Mac Edition

I've found lots of used ones, however it looks like there's many different makes and specs:

Sapphire Dual-X
Sapphire (flat case, sinlge fan)
Gigabyte
Msi
Asus Directcu II (3 slots wide!)
Xfx Ghost
...

Some vendors on Ebay, Amazon etc. show different specs regarding boot screen support, some claim compatibility up to Mojave some up to Catalina, some have 1 DP output instead of 2 miniDP, or are 3 slots wide instead of 2… One Gigabyte one also claims to support 4k at 60Hz, which adds to the confusion.

So here are 2 more questions if I may…

1) Regarding compatibility with different Mac OSs, boot screen capabilities etc, which of these makes would you recommend?
I've seen a single fan white Sapphire one that claims to be "genuine Apple", does it make any difference? other Sapphire ones are labelled Dual-X and have 2 bigger fans.
Is Sapphire the way to go for better compatibility with Apple?

2) My Mac connects to the display from another room via a 15 meter (50 feet) DP cable that's already installed in the wall so I gotta stick to that, does using an adapter from miniDP (the GPU output) to DP (the existing cable) cause any decrease in performance, or worse, create any OS compatibility issue?
In that case, should I opt for one of the ones that have a DP (not miniDP) output like the Asus Directcu II or some of the Sapphires?

Thanks for you patience tsialex?
all my best
P
 

tsialex

Contributor
Jun 13, 2016
13,094
13,300
HD7950 is too old, it's from 2012, lots of reports of cards dying lately.

If you want an AMD card that works for 10.8.5 with acceleration, get a R9 280X, it's the same Tahiti GPU but two, maybe even, three years newer.

You can flash most Tahiti cards with the Mac EFI of the real Sapphire HD7950 Mac Edition, no problem - just check if the card you find is one of that works fine on the 7950 flashing thread. A real Sapphire Mac Edition card is absurdly expensive this days, I'd buy a R9 280X that is know to work.

Your cable will degrade the signal, but I don't know if using an adapter from mini to normalDP will make it worse.
 

bsbeamer

macrumors 601
Sep 19, 2012
4,311
2,704
IF you can wait until late December or January, there will be a small surge of GPUs and MP5,1 hardware hitting the market.

Several MP5,1 & MP6,1 machines and components from 2013-2015 purchases with 5-7 year amortization will be officially retired on 1/1/2020. With COVID impacts, more companies than usual are looking to get quick cash grab from selling this hardware as they scale down their office spaces or shut locations.
 
  • Like
Reactions: RB13

Sample

macrumors member
Original poster
Dec 7, 2015
72
18
Thanks again tsialex! ?
I've checked out the R9 and it is indeed more recent, unfortunately I would need to go trough the process of adding SATA cables or an external PSU to meet its higher power requirements, after all I only work with audio with Logic Pro at 1080p, and rarely might like to watch a movie on my 4k (even if only at30Hz) monitor so now that I think about it... maybe the R9 might be a bit of an overkill...
I might as well try and risk it on a flashed Radeon HD 7950 hoping in lasts 3-4 years, maybe even the 7950 is already a bit overkill what do you think?

Hey bsbeamer! thanks to you too, unfortunately I cannot wait since I badly need one now, but thanks for the precious hint!
 
Last edited:

MacGarage

macrumors regular
Jun 18, 2017
189
88
Ohio
HD7950 is too old, it's from 2012, lots of reports of cards dying lately.

If you want an AMD card that works for 10.8.5 with acceleration, get a R9 280X, it's the same Tahiti GPU but two, maybe even, three years newer.

You can flash most Tahiti cards with the Mac EFI of the real Sapphire HD7950 Mac Edition, no problem - just check if the card you find is one of that works fine on the 7950 flashing thread. A real Sapphire Mac Edition card is absurdly expensive this days, I'd buy a R9 280X that is know to work.

Your cable will degrade the signal, but I don't know if using an adapter from mini to normalDP will make it worse.
My SAPPHIRE Radeon HD 7950 in my 2010 cMP died last week. I use a 30" Cinema Display.

This eBay seller was quick in shipping and I was able to get back up and running with a 10.14 compatible card:

 

tsialex

Contributor
Jun 13, 2016
13,094
13,300
Thanks again tsialex! ?
I've checked out the R9 and it is indeed more recent, unfortunately I would need to go trough the process of adding SATA cables or an external PSU to meet its higher power requirements, after all I only work with audio with Logic Pro at 1080p, and rarely might like to watch a movie on my 4k (even if only at30Hz) monitor so now that I think about it... maybe the R9 might be a bit of an overkill...
I might as well try and risk it on a flashed Radeon HD 7950 hoping in lasts 3-4 years, maybe even the 7950 is already a bit overkill what do you think?

Hey bsbeamer! thanks to you too, unfortunately I cannot wait since I badly need one now, but thanks for the precious hint!
What you do on 10.8.5? If you can use it un-accelerated, you can buy a flashed RX 580 - it's a lot more sane that buying a 8+ years old card.

Btw, Mojave is incompatible with your dual Nehalem Xeons, audio stuttering will make you crazy. You will need to upgrade your processors to Westmeres too.
 
Last edited:

Sample

macrumors member
Original poster
Dec 7, 2015
72
18
Oh wow tsialex! I didn't know that:oops:… thought I might make it just by getting a metal compatible GPU…

Ok thanks, so here's the full picture:

I still work with Logic Pro 9.1.8 on OS X 10.8.5 (for TV networks) because I have hundreds of 15 years old Logic projects that constantly require to be opened with certain plugins and samples and for this job Logic X is not ok for me for several compatibility reasons.

So after flashing to 5,1 I installed Sierra on a separate SSD, btw on that OS Logic 9.1.8 has a visual lag, a kind of delay in the movement and click of the mouse, which makes it pretty difficult to work with… Could that be due to the old NVIDIA GeForce GT 120 512 MB? I wonder.. but I digress

I was finally planning to install Mojave on a new SSD and using latest Logic Pro X there so that I can switch between the two OSs (Mountain Lion and Mojave) depending on what project I'm working on.

So far I've just finished cleaning a few weeks ago the 11 years old Mac Pro, repasting the 2 CPUs and replacing the ageing Northbridge clips plus repasting its CPU, apart from that it is still all original…

Crazy thought... Is there any way to keep two GPUs connected and switch between one another? ahah sorry clearly not an expert ?
 

bsbeamer

macrumors 601
Sep 19, 2012
4,311
2,704
Is there any way to keep two GPUs connected and switch between one another?

There "SORT OF" used to be a way to do this with PCIe expansion boxes, but using the expansion box as primary GPU was always problematic.
 

tsialex

Contributor
Jun 13, 2016
13,094
13,300
Oh wow tsialex! I didn't know that:oops:… thought I might make it just by getting a metal compatible GPU…

Ok thanks, so here's the full picture:

I still work with Logic Pro 9.1.8 on OS X 10.8.5 (for TV networks) because I have hundreds of 15 years old Logic projects that constantly require to be opened with certain plugins and samples and for this job Logic X is not ok for me for several compatibility reasons.

So after flashing to 5,1 I installed Sierra on a separate SSD, btw on that OS Logic 9.1.8 has a visual lag, a kind of delay in the movement and click of the mouse, which makes it pretty difficult to work with… Could that be due to the old NVIDIA GeForce GT 120 512 MB? I wonder.. but I digress

I was finally planning to install Mojave on a new SSD and using latest Logic Pro X there so that I can switch between the two OSs (Mountain Lion and Mojave) depending on what project I'm working on.

So far I've just finished cleaning a few weeks ago the 11 years old Mac Pro, repasting the 2 CPUs and replacing the ageing Northbridge clips plus repasting its CPU, apart from that it is still all original…

Crazy thought... Is there any way to keep two GPUs connected and switch between one another? ahah sorry clearly not an expert ?
You can't use NVIDIA and AMD GPUs at the same time after High Sierra. Mojave will do the weirdest things with the UI when you have NVIDIA + AMD GPUs or when you have a supported plus an unsupported one from the same maker.

If you really use Logic Pro 9.1.8, un-accelerated won't cut for you. So, forget the idea of a unsupported GPU working un-accelerated via EFI drivers.

Maybe Parallels will work for you, opening Mountain Lion from Mojave. Parallels accelerated GPU support is fast enough for most Logic Pro usage.

Btw, Logic Pro 9.1.7/8 can be made to work with Sierra, if you don't use iCloud. Sierra supports RX 580, badly, but works.
 
  • Like
Reactions: Sample

Sample

macrumors member
Original poster
Dec 7, 2015
72
18
My SAPPHIRE Radeon HD 7950 in my 2010 cMP died last week. I use a 30" Cinema Display.

This eBay seller was quick in shipping and I was able to get back up and running with a 10.14 compatible card:

thanks for the info MacGarage:)
 

Sample

macrumors member
Original poster
Dec 7, 2015
72
18
You can't use NVIDIA and AMD GPUs at the same time after High Sierra. Mojave will do the weirdest things with the UI when you have NVIDIA + AMD GPUs or when you have a supported plus an unsupported one from the same maker.

If you really use Logic Pro 9.1.8, un-accelerated won't cut for you. So, forget the idea of a unsupported GPU working un-accelerated via EFI drivers.

Maybe Parallels will work for you, opening Mountain Lion from Mojave. Parallels accelerated GPU support is fast enough for most Logic Pro usage.

Btw, Logic Pro 9.1.7/8 can be made to work with Sierra, if you don't use iCloud. Sierra supports RX 580, badly, but works.

Ok tsialex, thanks a lot for your patience!? Hope I won't bother you for too long, your help is invaluable for me.
So at this stage, if I understood well, these are my only options:

1) Getting Logic Pro 9.1.8 to work flawlessly on Sierra but having Logic Pro X limited to the 10.4.1 version (LPX 10.5 requires Mojave).
Btw I already tried this by disabling iCloud in Sierra (which I’ve never actually activated in the first place) but the visual lag has not subsided…

Here’s Logic Pro 9.1.8 issue with Sierra in detail:

- never had crash issues
- sound is perfect, no glitches
- play and stop inputs from keyboard or mouse have NO lag
- dragging along any window has NO lag

- zooming from keyboard in the arrange window HAS a lag
- green elastic rectangle selection via mouse HAS a lag
- selecting a region with the mouse HAS a lag

- if I move to an area of the arrange window where no regions are present the lag reduces a lot!

does this behaviour ring any bells for you? What else could be causing the lag? Could the old GPU be the culprit?

Problem is also that my new LG 43UD79 4k monitor really doesn’t like the GT 120, at 1080p it won’t go over 30Hz (the old Philips monitor worked ok at 1080p at 60Hz but the lag issue was there already so it’s not the new monitors' fault). So in this 1st scenario I think that I would need to get a new GPU all the same…
Btw some visual lag is also present in LPX though a little less noticeable (sound is perfect there too).

2) Upgrading the two CPUs to Westmeres ones, purchasing the RX 580, installing Mojave on an SSD, and hoping Parallels is able to virtually run Mountain Lion and Logic Pro 9.1.8.

3) Upgrading the two CPUs to Westmeres ones, purchasing the HD 7950 or the R9, installing Mojave on an SSD, and hopping between Mojave to Mountain Lion by booting from different disks, hoping boot screen can be visible.

Let me know if there’s something that I’ve misunderstood:rolleyes:
Thanks again tsialex
P
 
Last edited:

tsialex

Contributor
Jun 13, 2016
13,094
13,300
Ok tsialex, thanks a lot for your patience!? Hope I won't bother you for too long, your help is invaluable for me.
So at this stage, if I understood well, these are my only options:

1) Getting Logic Pro 9.1.8 to work flawlessly on Sierra but having Logic Pro X limited to the 10.4.1 version (LPX 10.5 requires Mojave).
Btw I already tried this by disabling iCloud in Sierra (which I’ve never actually activated in the first place) but the visual lag has not subsided…

Here’s Logic Pro 9.1.8 issue with Sierra in detail:

- never had crash issues
- sound is perfect, no glitches
- play and stop inputs from keyboard or mouse have NO lag
- dragging along any window has NO lag

- zooming from keyboard in the arrange window HAS a lag
- green elastic rectangle selection via mouse HAS a lag
- selecting a region with the mouse HAS a lag

- if I move to an area of the arrange window where no regions are present the lag reduces a lot!

does this behaviour ring any bells for you? What else could be causing the lag? Could the old GPU be the culprit?

Problem is also that my new LG 43UD79 4k monitor really doesn’t like the GT 120, at 1080p it won’t go over 30Hz (the old Philips monitor worked ok at 1080p at 60Hz but the lag issue was there already so it’s not the new monitors' fault). So in this 1st scenario I think that I would need to get a new GPU all the same…
Btw some visual lag is also present in LPX though a little less noticeable (sound is perfect there too).

2) Upgrading the two CPUs to Westmeres ones, purchasing the RX 580, installing Mojave on an SSD, and hoping Parallels is able to virtually run Mountain Lion and Logic Pro 9.1.8.

3) Upgrading the two CPUs to Westmeres ones, purchasing the HD 7950 or the R9, installing Mojave on an SSD, and hopping between Mojave to Mountain Lion by booting from different disks, hoping boot screen can be visible.

Let me know if there’s something that I’ve misunderstood:rolleyes:
Thanks again tsialex
P
I'm not a Logic user, but I have friends that are and they ask me for support constantly. While I know most of the problems, I don't experience it myself.

GT120 is a rebadge for a 2008 GPU (9500GT), with just 512MB of VRAM, any tests that you'll do with Sierra will be affected by it. It has lags on everything, don't you notice it with Safari too? I had to use one recently when my RX 580 failed and I was mad half the time with the wimp performance and constant lags.

You will need two de-lidded (or de-lid yourself) Westmere Xeons, look at X5677 if you just need two fast quad-cores or X5675/X5680/X5690 if you want hexa-cores, this is a requirement for any audio work after 10.13.6. I'd go for two X5680.

Don't you have a friend with a RX 580 that you can borrow to install and check Sierra plus Logic 9.1.x?
 
Last edited:
  • Like
Reactions: Sample

Sample

macrumors member
Original poster
Dec 7, 2015
72
18
I'm not a Logic user, but I have friends that are and they ask me for support constantly. While I know most of the problems, I don't experience it myself.

GT120 is a rebadge for a 2008 GPU (9500GT), with just 512MB of VRAM, any tests that you'll do with Sierra will be affected by it. It has lags on everything, don't you notice it with Safari too? I had to use one recently when my RX 580 failed and I was mad half the time with the wimp performance and constant lags.

You will need two de-lidded (or de-lid yourself) Westmere Xeons, look at X5677 if you just need two fast quad-cores or X5675/X5680/X5690 if you want hexa-cores, this is a requirement for any audio work after 10.13.6. I'd go for two X5680.

Don't you have a friend with a RX 580 that you can borrow to install and check Sierra plus Logic 9.1.x?
Dear tsialex, finally I have some updates, I still haven't purchased the new CPUs, as suggested I looked for a spare RX 580 but couldn't find one, on the other hand I found a dirt cheap R9 280 (not 280X), the card works but looks like the lag is probably caused by something else, I know you're not a Logic user but maybe looking at the lag behaviour in video might ring some bells to you?

Here's a video of the issue that I've uploaded on Youtube: (keep sound on to hear mouse click please)


The interesting thing is that, as you can see in the second part of the video, if I move to an area where no regions are present the lag reduces a lot:oops:
Could it be the old CPUs?

If this is going off topic please tell me and I'll post it in more appropriate sections.
thanks again..
 

Sample

macrumors member
Original poster
Dec 7, 2015
72
18
I'm not a Logic user, but I have friends that are and they ask me for support constantly. While I know most of the problems, I don't experience it myself.

GT120 is a rebadge for a 2008 GPU (9500GT), with just 512MB of VRAM, any tests that you'll do with Sierra will be affected by it. It has lags on everything, don't you notice it with Safari too? I had to use one recently when my RX 580 failed and I was mad half the time with the wimp performance and constant lags.

You will need two de-lidded (or de-lid yourself) Westmere Xeons, look at X5677 if you just need two fast quad-cores or X5675/X5680/X5690 if you want hexa-cores, this is a requirement for any audio work after 10.13.6. I'd go for two X5680.

Don't you have a friend with a RX 580 that you can borrow to install and check Sierra plus Logic 9.1.x?

Hi tsialex, I think I'll move on to Mojave after all... if I can disturb you again I have 2 more questions:

1) I've seen that in order to upgrade to Mojave I need to update the boot rom too (I have MP51.007F.B03), will that create any problem when I boot from Mountain Lion on the other drive? Will it still work or do I risk losing Mountain Lion compatibility or even bricking?

2) If I decide to go for the hexa-cores, what about the risk of overheating the Northbridge? I'd like to improve the CPU just the amount I need in order to be compatible, everything over that I would like to avoid if not strictly mandatory... Would I any be safer with the X5677 or it doesn't make any difference safety-wise?

thanks again..
 

tsialex

Contributor
Jun 13, 2016
13,094
13,300
Hi tsialex, I think I'll move on to Mojave after all... if I can disturb you again I have 2 more questions:

1) I've seen that in order to upgrade to Mojave I need to update the boot rom too (I have MP51.007F.B03), will that create any problem when I boot from Mountain Lion on the other drive? Will it still work or do I risk losing Mountain Lion compatibility or even bricking?

BootROM upgrades don't remove the capability of booting previous releases, you can boot 10.6.4 with 144.0.0.0.0, it's the GPU support that is the game changer.

Bricking is not directly related to the upgrade, but to the 10 or 11+ years of cruft inside the NVRAM volume.

2) If I decide to go for the hexa-cores, what about the risk of overheating the Northbridge? I'd like to improve the CPU just the amount I need in order to be compatible, everything over that I would like to avoid if not strictly mandatory... Would I any be safer with the X5677 or it doesn't make any difference safety-wise?

thanks again..
Northbrige overheating is related to broken heatsink pins, not to the processor itself.

Westmere processors are a lot cooler than Nehalem ones, even the fastest hexa cores, X5690/W3690, are still cooler than the old quads.
 
  • Like
Reactions: Sample

Sample

macrumors member
Original poster
Dec 7, 2015
72
18
BootROM upgrades don't remove the capability of booting previous releases, you can boot 10.6.4 with 144.0.0.0.0, it's the GPU support that is the game changer.

Bricking is not directly related to the upgrade, but to the 10 or 11+ years of cruft inside the NVRAM volume.


Northbrige overheating is related to broken heatsink pins, not to the processor itself.

Westmere processors are a lot cooler than Nehalem ones, even the fastest hexa cores, X5690/W3690, are still cooler than the old quads.

ok got it thanks tsialex!!
 

Sample

macrumors member
Original poster
Dec 7, 2015
72
18
BootROM upgrades don't remove the capability of booting previous releases, you can boot 10.6.4 with 144.0.0.0.0, it's the GPU support that is the game changer.

Bricking is not directly related to the upgrade, but to the 10 or 11+ years of cruft inside the NVRAM volume.


Northbrige overheating is related to broken heatsink pins, not to the processor itself.

Westmere processors are a lot cooler than Nehalem ones, even the fastest hexa cores, X5690/W3690, are still cooler than the old quads.

Hi tsialex, finally in the process of purchasing the 2 delidded Westmere hexacore X5675 CPUs for my 4,1 to 5,1 Mac Pro.
This is a pic I took 2 months ago when I replaced the failed Northbridge clips, the thermal pads on both the heatsinks had “sweated” a lot over the board in these 10 years and I cleaned the board, since I will be repasting the CPUs do you think I should also replace the pink thermal pads or are they ok like this? Mac has been perfect in these 2 months..

If yes, I’ve made some research on the forum and I gather the pink thermal pads should be 2mm thick for the heatsinks on a dual 4,1 with delidded CPUs, can you confirm 2mm?
Also does it have to be the original pink with "clothy" texture kind or the blue ones are ok too?

Thanks again:)..


cMP 4.1 thermal pad.jpg
 

tsialex

Contributor
Jun 13, 2016
13,094
13,300
Hi tsialex, finally in the process of purchasing the 2 delidded Westmere hexacore X5675 CPUs for my 4,1 to 5,1 Mac Pro.
This is a pic I took 2 months ago when I replaced the failed Northbridge clips, the thermal pads on both the heatsinks had “sweated” a lot over the board in these 10 years and I cleaned the board, since I will be repasting the CPUs do you think I should also replace the pink thermal pads or are they ok like this? Mac has been perfect in these 2 months..

If yes, I’ve made some research on the forum and I gather the pink thermal pads should be 2mm thick for the heatsinks on a dual 4,1 with delidded CPUs, can you confirm 2mm?
Also does it have to be the original pink with "clothy" texture kind or the blue ones are ok too?

Thanks again:)..


View attachment 1689623
Your's thermal pad still looks good, just need to be cleaned. Some gently cleaning with IPA + cotton buds will give a better appearance.
 
  • Like
Reactions: Sample

Sample

macrumors member
Original poster
Dec 7, 2015
72
18
one laaaast thing if I may:

At the moment I have 32 Gb of ram:
6 sticks of 2Gb at 1066 GHz
2 sticks of 8Gb at 1333 GHz (bought from OWC a while ago)

Can I use the X5675 (1333) CPUs with mixed 1333 and 1060 sticks?
 

Dayo

macrumors 68020
Dec 21, 2018
2,231
1,267
You can use mixtures of paired slower and faster speed RAM sticks.
All will operate at the slower speed.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.