What is the fastest memory for DDR400 speeds

I intend to purchase an Abit IC7-Max3 and a Northwood 3.4 Ghz so; Question (1) what is the fastest memory I can use in this machine if I do NOT want to overclock it at this stage. I presume the starting point would be the TWINX1024RE-3200LL. However in this article; [url]http://www.thetechlounge.com/review.php?directory=corsair_512_3500&page=1[/url] on page 3 the timings given for the 3500 memory were 2-2-2-5 with a voltage of 2.8v at 414 Mhz (misprint at 214 Mhz?). So if they are running at 2-2-2-5 at 414 Mhz they will presumably also run at 400 Mhz with these same timings. Immediately this appears to be better than the 3200LL advertised timings which are are only 2-3-2-6. Question (2) An article at [url]http://www.xbitlabs.com/articles/cpu/display/amd-ad-astra_6.html[/url] indicates in the table that although the bandwidth is 25% more between 400 Mhz and 500 Mhz memory, the latencies are not much different at 12.5 ns and 12.0 ns respectively, by how much of an increase in percentage do these two factors combined increase P4 performance? With the higher speed memory such as PC3700, PC4000, PC4400 the latencies are increased presumably to cope with the faster speeds and a previous answer to a post on this site stated that "The PC3700 will only run the 3,4,4,8 timings due to the ICs used." Is this because the same IC's are used on the faster memories as on the PC3200 memory? It looks like you have a choice between a small car with the full complement of gears or a Ferrari with only the first two gears! Or is there a technical reason the faster memory cannot have lower latencies similar to PC3200? Question (3) What are the latencies you can use if you run all these faster memories at only 3200 speed? are they better, worse or equal to the 3200LL? I tried comparing with another review of the PC4000 memory at [url]http://www.thetechlounge.com/review.php?directory=corsair_twinx_512_4000&page=1[/url] but comparing it with the first review is like comparing apples with oranges. I am even more confused than before I started researching this subject, but I look forward to any answer that can shed light on my problem.

The fastest memory for that, without overclocking, would be TwinX1024-3200LL, without the [b]RE[/b] in the name. I think you'd have some serious issues trying to get registered ECC memory to work with that board, even if it says it's ECC compatable. P4's don't like it at all. As for PC3500 memory, Corsair doesn't make it anymore due to the lack of IC production. Those 2-2-2-5 timings you say these people got are unheard of and VERY good, most modules probably won't go that fast. As for the 25% bandwidth increase of PC4000, to get that increase, you'd have to overclock your FSB to 250MHz or a 1000MHz FSB (Normally 800), so to reap the benefits, you have to really turn up the speed... However, the latencies DO go down as the speed goes up, because there is a physical limitation to how fast certain charges of electricity build up and dissipate and such, basically, the memory can only function so fast, but here's the thing: With memory running at 250MHz and CAS 3-4-4-8 and memory running at 200MHz and CAS 2-3-2-6, the 250MHz has enough of a speed boost to get much better performance regardless of the slower latencies. However, you should check this out: [url=http://houseofhelp.com/forums/showthread.php?t=20057]Click Me[/url] it contains a link to a very good comparison of memory speed v.s. latencies. Alright, where am I now? (Big post!) Ahh, yes... running faster memory at slower speeds... The PC4400 memory Corsair makes is CAS 3 memory. It will still be CAS 3 memory even if you underclock it to PC3200. The IC's aren't designed or meant to be run at CAS 2 at any speed. Granted, there's always odd quirks that might work, but it's not something you'll readily find. PLUR CK