Solved Memory timings

Ocz technology / Ddr2 800
December 9, 2011 at 22:14:47
Specs: Windows 7 64-bit, 2.81Ghz/4 GB
Hey, just a quick question...I built this computer about 4 years ago and put in two 1 Gb sticks of OCZ PC2 6400 RAM. The sticker on the RAM indicates timings of 5-5-5-12 but I opened up CPU-Z and noticed the timings in the SPD tab for JEDEC #3 were 5-5-5-15...I can change the tRAS from 15 to 12 using MemSet but I don't know if I should leave it at 15 or reduce it to 12. I doubt this makes that big of a difference but I'm just trying to get the most out of a 4 year old PC.

Not sure if these are the exact same RAM sticks but it seems to be close to what I have:

See More: Memory timings

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December 10, 2011 at 05:57:57
✔ Best Answer
When RAM of differing specs are installed together, ALL the RAM will run at the settings of the weakest link. So if you have "fast" RAM with timings like 4-4-4-12 & team it up with "slow" RAM of 6-6-6-18, ALL the RAM will run as 6-6-6-18 unless the timings are configured manually. However, CL6 RAM may become unstable if it's run at CL4.

Same goes for RAM frequency. If you team up DDR2-800 with DDR2-667, ALL RAM will run as DDR2-667. And if you attempt to run DDR2-667 at DDR2-800 frequency (400Mhz), it will likley become unstable or prevent the system from booting.

Your problem isn't timings, it's that your DDR2-800 is only running at 625MHz. Are you 100% sure that all your RAM is DDR2-800? Because DDR2-667 will run at 625MHz when it's paired up with an AMD CPU with 14x multipler. That's the way the memory divider works with that particular config. And since you've said there's no way to increase the RAM frequency setting in the BIOS, the only way to increase the RAM speed would be to increase the CPU frequency. The problem with raising the CPU frequency is that doing so will increase the HT frequency. The HT frequency doesn't require overclocking & should be kept as close to it's default speed of 1000MHz as possible. If the HT bus is too far out of spec, the system may become unstable.

This table lists the resulting memory settings based on the CPU frequency & multiplier settings:

The bottomline is you have a crappy motherboard with a crappy BIOS that has very limited overclocking options. There is no work-around. Either live with it or buy a new board.

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December 10, 2011 at 09:59:34
I'm 100% sure all my sticks are 800 MHz. When I was installing them I booted up the PC after popping in each RAM module and saw that my BIOS detected the RAM at 800 MHz as long as I didn't have the other brand plugged in as well (did it several times out of desperation just to check each module). I have no clue why my RAM is running at 625 MHz, but thanks for the awesome info regardless! I guess since it isn't broken I won't fix it :P

Also, just out of curiosity...If I could get my OCZ modules to run at CL6 thus matching the CL6 of the Kingston modules would my system become unstable?

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December 10, 2011 at 18:26:08
Got it to work, there was a hidden menu in my BIOS which allowed me to OC the memory to 800 MHz at CL5, thanks!

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