Timing issue between different pairs?

Hey Ramguy,

I curently have a pair of 6400C4PRO XMS2 4-4-4-12 installed. 800mhz

Now I have just installed a pair of 6400PRO 5-5-5-12 that I just bought.

(I tried to buy a second pair of C4PRO but no one seemed to have in stock).

I noticed that only the LED bars on the 5-5-5-12 were fully lit. The 4-4-4-12 were normal. So, just curiosity sake I ran Memtest on all four installed and noticed failing the first four tests.

What I did next was I tested each stick individually and all were fine.

Should I change the timings. If so to what settings. I have attached screenshots of the timings.

Thanks for the Help!

Adobe40

It's never advised to mix and match DRAM versions. When the version of the DRAM is of a different integer, this means that the DRAM is of a different fabrication/manufacturer and different fabrications have different timing settings.

As well, when you are populating with four DRAM slots you are changing the dynamics of the system. The on motherboard memory controller is not able to respond as quickly (load and access the DRAM) with four DRAM slots as it did with two DRAM slots. Thus, you would need to drop the speed of the DRAM to allow a stable relationship between the on motherboard memory controller and the DRAM. But this is if you had four of the same model and version.

I can't see this working.

Thanks Derek..

I thought that would be the case. :biggrin:

Further questions.....are you overclocking your system? If you are, you'll most likely have to reduce the overclock to handle the stress on the northbridge chipset which has the memory controller in it. Also, when overclocking and populating all four DIMM slots, a small voltage increase to the northbridge chipset typically brings about a greater stability factor.

Second, when you installed the second set of RAM, did you just install them and then run? If you did, I'd suggest you manually readjust your memory timings in your BIOS to match the slower of the two sets......this will force the "faster" set to run at the "slower" set's timings, negating any timing issues.

And, yes, you can certainly "underclock" or slow the timings, it's called loosening the timings" on your or any memory. Very commonly done, esp. in overclocking aggressively with high FSB's.