Kudos Posted July 17, 2008 Posted July 17, 2008 (edited) I have a Foxconn X38A motherboard and I finally figured out that my memtest86 and prime95 errors were due to not having the TWR, TRFC, TWTR, TRRD, and TRTP timings set high enough. They were set at 3-64-3-2-3 and I changed them to 4-64-4-3-4 (4-4-4-12 memory). Since then memtest86 and prime95 work perfectly. Does anyone have an explanation of exactly what these timings mean, and where you can find the timings settings for your RAM (I have Geil DDR2 800 RAM). I was also wondering how much these timings affect performance/stability. Any comments are welcome. Edited July 17, 2008 by Kudos Share this post Link to post Share on other sites More sharing options...
hardnrg Posted July 17, 2008 Posted July 17, 2008 I have Geil Ultra 2x1... when I ran it at 4-4-4-12-2T or 4-4-4-12-1T, I found some settings that worked well for the secondary timings on my 680i: tRRD: 3 (or 4) tRC: 18 (or higher) tWR: 5 (or 6) tWTR: 9 (or 10) tREF: 7.8us I can't set tRFC in my BIOS... and I either don't have tRTP (Precharge Time) visible anywhere, or it's called something else There are various DDR2 overclocking guides floating around that give recommend values and ranges that generally work well... you can read about them in depth to see exactly how they work, but it gets immensely complicated, and it's not actually necessary to fully understand them, just the relations that some have, e.g: tRC >= tRP + tRAS some people say tRC >= tRP + tRAS + 2... and I find this is more stable when really pushing the clock speed Share this post Link to post Share on other sites More sharing options...
Syngensmyth Posted July 17, 2008 Posted July 17, 2008 tRC >= tRP + tRAS some people say tRC >= tRP + tRAS + 2... and I find this is more stable when really pushing the clock speed This would be interesting but my Googles are not finding the above info. Any links handy available? Share this post Link to post Share on other sites More sharing options...
hardnrg Posted July 17, 2008 Posted July 17, 2008 nope... but if you google: ddr2 overclocking guide, several clicks later you should find something or: ddr2 overclocking tcl trp trcd tras trc etc Share this post Link to post Share on other sites More sharing options...
Praz Posted July 17, 2008 Posted July 17, 2008 A friend has an explanation posted of all the timings you asked about. Timing Explanations Share this post Link to post Share on other sites More sharing options...
Syngensmyth Posted July 17, 2008 Posted July 17, 2008 Praz, thanks. That is exactly what I'm looking for. I've never seen it so well put. Share this post Link to post Share on other sites More sharing options...
Kudos Posted July 17, 2008 Posted July 17, 2008 (edited) Wow thanks guys this was very helpful. :thumbs-up: One problem I'm having is that there does not seem to be a selection for the command rate (e.g. 1T, 2T etc) in my BIOS. I'm guessing my RAM is at 2T though. Edited July 17, 2008 by Kudos Share this post Link to post Share on other sites More sharing options...
Praz Posted July 17, 2008 Posted July 17, 2008 Quite a few Intel DDR2 based boards have no manual manipulation available for Command Rate. When the option is unavailable the chipset defaults to 2N. It requires a strong chipset and good memory to run much over 900MHz at 1N. Share this post Link to post Share on other sites More sharing options...
Syngensmyth Posted July 17, 2008 Posted July 17, 2008 cpuz and other programs will let you know if 1 or 2t. BIOS screen, memtest86 ... others. Share this post Link to post Share on other sites More sharing options...
dr_bowtie Posted July 18, 2008 Posted July 18, 2008 I have also found that tfrc will change trc on AMD boards...so it must be related somehow... not sure is changing trc will effect trfc though...I havent seen were trfc is as big an issue on Intel as it is on AM2 boards with Brisbane CPUs... Share this post Link to post Share on other sites More sharing options...
Waco Posted July 18, 2008 Posted July 18, 2008 Practical definitions are worth a lot more than the actual technical definitions. If you really want to play with the more advanced timings you usually have to look up the spec-sheets of whatever modules are used on the memory you're running. Share this post Link to post Share on other sites More sharing options...
Kudos Posted July 18, 2008 Posted July 18, 2008 Practical definitions are worth a lot more than the actual technical definitions. If you really want to play with the more advanced timings you usually have to look up the spec-sheets of whatever modules are used on the memory you're running.I would love to know where I could find that info on Geil RAM. Geil's website is not that great and I can find no actual spec sheets for my RAM. Share this post Link to post Share on other sites More sharing options...
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