cMP 4.1/5.1 only runs on SingleChannel

[MadBlue]

Hi everybody,

I have an issue with my dual socket cMP 4.1=>5.1.
I'm using 6 PC1333 RDIMMs with 8GB each in the Slots 1, 2, 3 and 5, 6, 7. But my cMP just arrives SingleChannel Bandwiths and CPU performance is a bit low.

On my cMP 4.1=>5.1 single socket, the same memory runs at full TrippleChannel speed on Slots 1, 2 and 3... PRAM Reset etc. didn't had any effect.

Also on DualChannel Config (1, 2 + 5, 6) the mac is running only with SingleChannel speeds.

Do you have an advice for me?
Thanks!

 

[A Hobo]

Hi everybody,

I have an issue with my dual socket cMP 4.1=>5.1.
I'm using 6 PC1333 RDIMMs with 8GB each in the Slots 1, 2, 3 and 5, 6, 7. But my cMP just arrives SingleChannel Bandwiths and CPU performance is a bit low.

On my cMP 4.1=>5.1 single socket, the same memory runs at full TrippleChannel speed on Slots 1, 2 and 3... PRAM Reset etc. didn't had any effect.

Also on DualChannel Config (1, 2 + 5, 6) the mac is running only with SingleChannel speeds.

Do you have an advice for me?
Thanks!

What CPUs you rocking?

 

[MadBlue]

Hi,
I'm running X5680s

 

[ActionableMango]

Any LEDs illuminated inside? What RAM is it and have you tried moving the "single channel" RAM to the other Mac Pro? How do you know what speed it is running at?

 

[flowrider]

Is all your RAM available? In "About This Mac" what does it show for the "Processor"?

Lou

 

[h9826790]

Can you post some screen capture? It's hard to know what exact problem you are facing at.

e.g. the system info -> memory page, and how you determine the memory speed, etc

 

[MadBlue]

Hi,

I'm using Elpida DDR3-1333 RDIMMs... all 9 Stick's the same model. 3 of them I'm using in the single Socket Mac, the other 6 in the Dual Socket Machine. In the preferences and "about my mac" everything is fine. It's showing 48GB RAM with DDR3-1333 Speed.

To determine the Bandwith I'm using GeekBench 4.
In my Single Socket Mac you can the the Bandwith changing with using 1, 2 or 3 sticks.
In my Dual Socket Mac it's stuck at about 6,4 GB/Sek, wich is Single-Channel Speed.
Also the Single-Core Performance is the same as in my Mac Pro Single-Socket using Single-Channel. So I'm very sure the system is not using tripple-channel mode.

Sören

 

[h9826790]

Hi,

I'm using Elpida DDR3-1333 RDIMMs... all 9 Stick's the same model. 3 of them I'm using in the single Socket Mac, the other 6 in the Dual Socket Machine. In the preferences and "about my mac" everything is fine. It's showing 48GB RAM with DDR3-1333 Speed.

To determine the Bandwith I'm using GeekBench 4.
In my Single Socket Mac you can the the Bandwith changing with using 1, 2 or 3 sticks.
In my Dual Socket Mac it's stuck at about 6,4 GB/Sek, wich is Single-Channel Speed.
Also the Single-Core Performance is the same as in my Mac Pro Single-Socket using Single-Channel. So I'm very sure the system is not using tripple-channel mode.

Sören

Can you take a picture of your processor tray about how you install the RAM?

I have both single and dual processor cMP. But I only use the single processor one, and has no GB4 performance figure on hand for the dual processor setup. May be other member here can tell if that's normal in GB4. If yes, then may be GB4 is not good for dual processor setup, not necessary means your Mac is in bad shape.

 

[handheldgames]

Hi,

I'm using Elpida DDR3-1333 RDIMMs... all 9 Stick's the same model. 3 of them I'm using in the single Socket Mac, the other 6 in the Dual Socket Machine. In the preferences and "about my mac" everything is fine. It's showing 48GB RAM with DDR3-1333 Speed.

To determine the Bandwith I'm using GeekBench 4.
In my Single Socket Mac you can the the Bandwith changing with using 1, 2 or 3 sticks.
In my Dual Socket Mac it's stuck at about 6,4 GB/Sek, wich is Single-Channel Speed.
Also the Single-Core Performance is the same as in my Mac Pro Single-Socket using Single-Channel. So I'm very sure the system is not using tripple-channel mode.

Sören

What type of rdimms? It should say 2rx4 or 4rx4 etc. We know 2rx4 works well.