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MP 1,1-5,1 Will this memory config work in triple channel?
- Thread starter rdalrt
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I would assume that you need to have 3x identical Dimm sizes per CPU - but I am not sure. Didn’t find any precise info how to place RAM with different sizes in a dual CPU Mac for tripple channel. Waiting for my additional memory to arrive this week and will have the same question that you have. Guess we will have to try out with geekbench and see what’s faster. The only thing clear to me is not to use the 4th and 8th DIMM slot.
It should work. I agree that using geek bench in different configurations to see if there is a change in performance.
Your setup can only works in triple channel. Each slot only connected via one channel. If not in triple channel, then at least one of the DIMM won't work.
However, that doesn't mean you have optimum performance (if that's the "triple channel" you really want to ask).
However, that doesn't mean you have optimum performance (if that's the "triple channel" you really want to ask).
Hmm, good point. Is there a recommended app/method for testing memory performance in this config vs six identical 8GB dimms?
GB3 is quite sensitive to the memory config, and has "memory performance" for you to compare.
Just to follow up on this, I had a chance to do some testing in GB3 (64 bit) today.
Test rig:
Mac Pro 4,1 flashed to 5,1.
Intel Xeon E5520 @ 2.26 GHz (memory runs at 1066)
2 processors, 8 cores
Running Mojave
Results: each config. run 3 times, these are the best results from each
Config. #1
48 GB of ram, six identical sticks in slots 1,2,3 & 5,6,7
Config. #2
64 GB of ram, 16GB in slots 1 & 5, 8GB sticks in 2,3 & 6,7 (the config. at the top of this thread)
Config. #3
24 GB of ram, six identical 4GB sticks in slots 1,2,3 & 5,6,7
Config. #4
32 GB of ram, eight identical 4GB sticks filling all slots
Not sure what it would all mean in terms of real world performance, but just thought I would post what I found.
Test rig:
Mac Pro 4,1 flashed to 5,1.
Intel Xeon E5520 @ 2.26 GHz (memory runs at 1066)
2 processors, 8 cores
Running Mojave
Results: each config. run 3 times, these are the best results from each
Config. #1
48 GB of ram, six identical sticks in slots 1,2,3 & 5,6,7
Memory Performance
| Single-core | 1778 | |
|---|---|---|
| Multi-core | 4153 |
Config. #2
64 GB of ram, 16GB in slots 1 & 5, 8GB sticks in 2,3 & 6,7 (the config. at the top of this thread)
Memory Performance
| Single-core | 1614 | |
|---|---|---|
| Multi-core | 2018 |
Config. #3
24 GB of ram, six identical 4GB sticks in slots 1,2,3 & 5,6,7
Memory Performance
| Single-core | 1825 | |
|---|---|---|
| Multi-core | 4282 |
Config. #4
32 GB of ram, eight identical 4GB sticks filling all slots
Memory Performance
| Single-core | 1712 | |
|---|---|---|
| Multi-core | 1967 |
Not sure what it would all mean in terms of real world performance, but just thought I would post what I found.
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It’s easy, despite the multi thread performance is doubled in the optimum memory config. I believe you can’t feel anything. If not using GB, most likely you can’t tell there is any difference.
And this is exactly what it means in real world - almost no difference in most of the time.
In general, just keep it simple. Install as much memory as you can. E.g. you can run 72GB now, then no need to stay at 64GB.
And this is exactly what it means in real world - almost no difference in most of the time.
In general, just keep it simple. Install as much memory as you can. E.g. you can run 72GB now, then no need to stay at 64GB.
I have a similar config with the same processors but running high sierra. I was having trouble installing memory in slot 2. It seems no matter what memory config I can only get single core 445 and multicore around 2900-3000. I am using geekbench 5. I tried 8Gb in slot 1,5 only, then 8gbx6 in slot 1,3,4,5,7,8. I get the exact same scores
