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How difficult is it to run 24 GB of fast RAM on X58? (X58 / Socket 1366 / Westmere)

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Mr. Friedchip

New Member
Mar 28, 2024

I own a Xeon X5690 that I like to use on my home workstation, along with 24 GB of RAM. It's enough computing resources for me that I don't care to upgrade to a later-gen platform. My problem: I'm having a hard time getting 24 GB of RAM to work any faster than at 1066 MHz. I'm at my third X58 mainboard and have tried 3 sets of DDR3 RAM sticks without good results.

FIrst set is an OCZ 6x 4GB PC-10666 that I bought early on (rated for 1333 MHz at CL 9, 1.65V). It works well at 1066 MHz, but whenever I set the DRAM clock at 1333 MHz, I hardly ever get the full amount detected during POST. 16 GB, 12GB, 8GB... It took a lot of rebooting at every startup on my 2 first (Asus) boards to get to 24GB. It seems even harder on my latest (Gigabyte) board. Raising Vtt a couple notches doesn't help, and I've given up on it for now.

Second set are G-Skill Ripjaws PC3-19200 (1.65V) It's actually 3 kits of 2x 4GB. I never got more than 16GB to be detected, even at 1066MHz!

Third set was 3 kits of G-Skill Ares PC3-12800 (1.50V). I made a layman's mistake and didn't reset CMOS before using them, they were never detected. Is it possible that I've fried them all feeding them 1.65V for just a few minutes?

I've read every thread I could find about X58, as well as Miahallen’s overclocking guide. Maybe these first-generation chips, with their on-die IMC and first to introduce triple-channel are just not mature enough to exploit all sorts of memory configs efficiently?

Would I have better chances of running at 1333 Mhz or higher if I bought 2 kits of 3x 4GB G-Skill RAM explicitly designed for triple-channel systems?

Would RAM rated at 1.5V have a better chance to run faster for some reason?

Do I need to look at the situation as a general overclocking problem, and first try to raise my BCLK, then try to raise my Vtt some more before touching the other clocks?

Thanks for reading. I appreciate any insight.
What board? Did you update the BIOS to the latest version? Are any of these memory kits you bought on their memory QVL (does X58 have any?).. I don't recall what that platform actually supports.

But how you're booting (not getting total capacity) and trying across multiple boards, sounds like a memory IMC problem (on the CPU)..... IF the platform supports it. List a board and I can check. The fact that it works at lower speeds tells me it doesn't like the larger capacity.

Would I have better chances of running at 1333 Mhz or higher if I bought 2 kits of 3x 4GB G-Skill RAM explicitly designed for triple-channel systems?
No. More RAM/more slots populated = slower supported speeds.
The current board is a Gigabyte X58A-UD7 revision 1. The past two were Asus P6X58D-E and P6T Deluxe v2. The Asus boards had their latest BIOS, the Gigabyte is still one step behind (F6 instead of F7). I'll test things again tonight with F7 and report back.

All these boards have QVLs that I had checked, but QVLs are always minimal. None of my sticks are on any QVL.

Gigabyte X58A-UD7 rev. 1 memory QVL
Asus P6T Deluxe v2 QVLs
Asus P6X58D-E QVLs

As you can see, very few 4 GB sticks are on these lists. And they are all sticks from chips manufacturers only (Samsung, Hynix).
These boards don't officially handle any Xeon CPUs either. (But aren't they basically just i7s with ECC support?)

More RAM/more slots populated = slower supported speeds.
I was afraid of this. Asus user manuals sort of hinted at it.
I don't have experience of that type of CPU/mobo, but maybe try 8GB modules? Get rid of the 2DPC question although the ram will probably be 2R. Still feels like 1DPC 2R has better chances than 2DPC 1R.
Updating to BIOS release F7 did not change much in terms of results. I does however provide me with a cool new layout showing more information on the RAM side, channel per channel. It turns out that my 6x 4GB on either of the 2 kits were always detected, but the board can decide whether or not to actually enable them:


When this happens I'm also shown this mysterious 'Recovering lost DRAM size' message right before execution is handed over to the bootloader. (I was unable to test its effect on effective RAM size because of unrelated OS problems at the time...)


Get rid of the 2DPC question although the ram will probably be 2R. Still feels like 1DPC 2R has better chances than 2DPC 1R.
Thanks for that. It got me to learn about daisy-chained RAM slots via this post on the MSI boards. 1DPC seems like it would be ideal. I did run into a couple of people who managed to make things work fast with 2DPC, though.

I've learned a lot looking into this. Thanks again.
Hey... can you attach the images here to the forum (so they wont disappear in time)? You should just be able to drag and drop the image in the body of the post.
Sure thing.

Another question: how worthwhile is it to pursue higher DRAM clock frequency, given that timings will be adjusted accordingly? Could it be that running at 1066 MHz CL 8-8-8 be as fast as 1333 MHz 9-9-9? Is there some sort of web-based calculator for this?

I'm asking because my board lowered the timings as such at one point:
I had better luck with older bios when running a full load of mis matched dimms. I think I was able to run up to 933, but to be fair, I only had 2GB dimms.