On Thu, Feb 01, 2007 at 03:05:08AM -0800, Francesco Pietra wrote: > With the old i386 machine very little info on (cheap) > ram. > > With tyan2895 K8WE/dual-opteron amd64 machine far more > info on the 8 mem modules (Kingston DDR ECC): width > 64bit, though non info on frequency. What is given is > the controller clock (66MHz) at surprisingly 32bit. > > Is that worthwhile, under such conditions, to pay for > expensive mem modules (in terms of speed I mean, the > security of ECC is another affair)
Well I have seen many messages on this list from people with various problems, all claiming to have run memtest for days on end and being absolutely sure their ram was perfect. When they then tried removing half their ram, had the problem go away, swapping in the opposite half of ram and having the problem come back, they finally understood that memtest doesn't catch all types of errors, and that the opteron demands quality memory. It doesn't have to be expensive, but it absolutely must be made to the spec it claims to be. If you claim a latency of 3 cycles, and you are really 3.02 cycles latency, figuring the memory controller isn't going to run the ram at exactly the spec you put in your SPD chip, well then the opteron will likely prove you wrong. It really does try to get the most from the ram. Well that's my theory on it at least. So far I have not personally run opterons, just athlon 64s, but kingston value DDR 400 ram worked perfectly. Given name brand ram doesn't have to cost particularly more than generic ram, why use generic when you can pay a few percent more for lifetime warenty ram that works. Even stuff like crucial and corsair isn't really that much more expensive (as long as you don't buy the crazy overclocking ram running at 1000MHz). Of course you could always follow the advice of the system/motherboard maker and buy what they have tested and qualified to work. In terms of using 333MHz or 400MHz or whichever ram, well I guess that depends a lot on what type of work you do. If it is very memory intensive, then the extra bandwidth of 400Mhz is probably worth it. If you are mainly running cpu intensive, with not too much actual memory access, then you may want to save a bit (if 333MHz is cheaper at all anymore) on the ram, and get a faster cpu instead. Of course buying the fastest posible cpu and putting in the cheapest slowest ram just doesn't make sense in general, but I guess it might for some people. -- Len Sorensen -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
