Asus A7N8X Dlx w/XMS TWINX3200C2PT - Timings issue

Hey all,

I've got a slight problem with my TWINX3200C2PT memory. As you can see from the heading, I'm running an Asus A7N8X Dlx motherboard with a 3200+ Barton (200/400 Mhz FSB, however you may think of it) and I recently upgraded to the 1 GB (2x512) corsair chips, from Samsung stuff that was ancient from the early days of DDR400, and my timings seem to be having trouble. My timings before I upgraded seemed to be 3-3-3-8, and now in the BIOS they are still registering as 3-3-3-8. Here's some info I've pulled from my BIOS and from the nvidia system utility (nTune).

BIOS:

SDRAM Active Precharge Delay: 8

SDRAM RAS to CAS Delay: 3

SDRAM RAS Precharge Delay: 3

SDRAM CAS Latency: 3T

DDR Reference Voltage: 2.6V

Also CHIP Voltage: 1.5V (this is available due to the Uber BIOS I'm running, but I'm not sure which "chip" voltage it is for, possibly memory, possibly processor, not sure)

I've seen some of the Corsair memory on newegg at voltages of 2.75, but the memory I bought did not specify. Also, my options in the BIOS are 2.6, 2.7, 2.8, and 2.9 for the DDR Reference Voltage.

nVIDIA nTune:

Row Address Strobe (T(RAS)): 8

RAS to CAS Access (T(RCD)): 3

Memory Bank Switch (T(RP)): 3

nTune reports, Voltage Interface Level SSTL: 2.5V

Memtest86:

CAS 3-3-3-8

According to newegg, the memory timings should be 2-3-3-6...

I'm a bit new to the modern memory stuff, so if there's anyone that can help me out in interpretting that stuff and figuring out why it isn't running at the normal spec speed, I'd be very thankful. Here is the link from newegg for the memory I bought: http://www.newegg.com/Product/Product.asp?Item=N82E16820145450

Thanks a ton!

Brian

The SPD is set to JEDEC values.

You would have to manually set the timings.

SDRAM Active Precharge Delay: 6

SDRAM RAS to CAS Delay: 3

SDRAM RAS Precharge Delay: 3

SDRAM CAS Latency: 2.5

DDR Reference Voltage: 2.7

According to newegg, the memory timings should be 2-3-3-6...

Only on Intel and Socket 754/939 AMD platforms. Unfortunately, your AMD platform is Socket A (462); on such platforms, the memory timings should be 2.5-3-3-6. (Though on your nForce2 chipset motherboard, you should really be using 2.5-3-3-11 due to the findings in professional reviews that the nForce2 chipset delivers its greatest memory bandwidth with a Tras setting of 11 or 12. On newer Socket 754/939 platforms, the nForce3 chipset works best at 2-3-3-10, while the nForce4 chipset is optimal at 2-3-3-7 -- all results with the TWINX####-3200C2 kit.)

Thanks guys!

I tried out my memory on 2.5-3-3-6, 2.5-3-3-11, and 2.5-3-3-12, burned it on each, and then benchmarked it with Sandra and found 2.5-3-3-11 to be the best timing. Thanks everyone for the help! Everything is working fine.

Brian

Only on Intel and Socket 754/939 AMD platforms. Unfortunately, your AMD platform is Socket A (462); on such platforms, the memory timings should be 2.5-3-3-6. (Though on your nForce2 chipset motherboard, you should really be using 2.5-3-3-11 due to the findings in professional reviews that the nForce2 chipset delivers its greatest memory bandwidth with a Tras setting of 11 or 12. On newer Socket 754/939 platforms, the nForce3 chipset works best at 2-3-3-10, while the nForce4 chipset is optimal at 2-3-3-7 -- all results with the TWINX####-3200C2 kit.)

Very interesting facts. I recently RMA'd some TwinX 1024-3200XLPT DIMMs that were giving me trouble at default timings on my NF4 motherboard even at default values of 2.5-3-3-6, 2T. I never even tried setting it at 2-2-2-5 because I was getting repeated crashes at the slower timings. I also didn't know that Tras might need to be longer than default. Do you have any advice for timings for 2 sticks of CMX512-3200XLPT on my NF4 motherboard?

Ron

Ron,

My Tras suggestions are due to the peculiarities of NVIDIA chipsets in general. With your nF4 mobo, the Tras is best set at 7 unless you have memory which requires a higher (longer) Tras value.

My memory is TwinX 1024-3200XLPT. The NF4 motherboard is an Asus A8N-SLI Premium. The BIOS defaults on this RAM were 2.5-3-3-6 (although rated at 2-2-2-5). I thought my timings were very "relaxed" by leaving them at those defaults, as opposed to setting them at the Corsair specs. I never knew that there was any possibility that they might be too tight -- i.e., that the Tras might need to be lengthened even more. That was never suggested by the Corsair techs on this forum. Have you read reviews or lab analyses suggesting that this particular RAM could be more stable at Tras 7? Would you recommend running it at 2-2-2-7?

I have to ask rather than do the experiment because it's already been twelve days since Corsair received my DIMMs, and I still don't have the replacements. I'm just trying to gather some ideas on things to try if the new RAM causes BSOD crashes like the original ones did. (My machine is perfectly stable on one 512MB stick of Corsair ValueSelect PC3200, so the previous instability seems clearly to have been the 3200XL which paradoxically cost 2.5 x as much as the VS.)

Thanks,

Ron

Thanks very much for the info, but I'm not sure I understand the point about the BIOS. The computer failed Prime95, often within just a few minutes, with the original 3200XLPT DIMMs, both singly and with both installed. It also gave BSODs several times a day. The machine is perfectly stable with the exact same BIOS settings with ValueSelect PC3200 -- runs Prime95 all day and all night and hasn't crashed in over two weeks. How could this be a BIOS issue??

By the way, I am running the very latest non-beta BIOS. When you say that this motherboard requires manual setting, do you mean that it's inherently incapable of detecting SPD values?

Ron

I did set those values manually. I increased the voltage to 2.8, but I chose to leave the timings at default -- i.e., at values that should NOT stress the RAM. Even with these relaxed timings, BOTH DIMMs crapped out in Prime95 within minutes, whereas the ValueSelect DIMM would run that stress test indefinitely.

Since my last post, the replacement TwinX 1024 3200XLPT arrived from Corsair (thank you very much), and the new DIMMs perform perfectly -- Prime95 runs overnight without errors, and there are NO MORE of those cursed BSODs. The computer is running so well at 2.5-3-3-5, 1T, that I don't think I'm even going to experiment with trying to take it to 2-2-2-5. It's just so good to have my machine stable once more!

It cost me $45 (cost of the VS512MB-400 DIMM) to troubleshoot my problem, but the only conclusion I can reach is that both of the original DIMMs went bad. I'd give a lot to know what could have caused that.

Ron

Oh, yes, I did send them back. In the original thread in which Corsair approved my RMA, I posted the good results with the new modules and asked for a post-mortem on the ones I returned, but I didn't get a reply yet. The RMA # was R99612 if that would help you figure out what they found when testing the original DIMMs.

Ron