Need RAM for OC'd Mobile 2500+

I'm going to get a mobile 2500+ and overclock it. The FSB will be somewhere around 215-230... depending on my luck. I read in a memory sticky that your RAM should match or surpass in its speed with the CPU FSB speed.

PC3200 = 200mhz, so must go faster
PC3500 = 217mhz, so it might suffice
PC3700 = 234mhz (this right?), so this would be fine

Is this true that your memory speed should match or surpass that of your CPU's FSB speed? I see a ton of people with FSB's well past 200 who are using PC3200 memory. I read that this would have a reverse effect and would cause a slower machine.

Perhaps these people with PC3200 are overclocking their RAM to be like PC3500?

What RAM do you guys recommend? Give me the top three recommendations in order please.

I am in the same boat! For the past week I have been doing research.. I am going to guess what people are going to tell you.. maybe then I can tell if my research has paid off..


If you want to go cheap, and get up to around 220 or so with fairly tight timings, go with the Buffalo memory from newegg with CH-5 chips on it.

If you want to go all out, get some sticks with BH-5 or BH-6 from www.zipzoomfly.com..

Since you are on an AMD platform the Hynix D43 chipped memory is not the best bet because of the loose timings..

let's see if the rest agree..

Im not sure.......

Im trying to get RAM as well. Personally I have been somewhat disapointed by my CH-5. The highest it will go with (2-2-3-6) is 225.

And BH-5 is gone forever, and no vender has them anymore. Plus upping CH-5's voltage will only hurt its performance and what not. What Im getting is actually PC4000. Yes the timings arent great, but the stuff Im getting is ( 2.5-4-4-8) not (3-4-4-8)

I figure since its so close to my CH-5's timings, (and ive personally tested this) it wont really make a difference.

All I loose is 300mbs/sec @ the same speed in memtest86. Instead of the usual 1038 mb/sec @ 225 its 775mb/sec.

It may seem like a big drop, but Im sure it will be atleast equal to or greater than when it runs @ 500mgz. Plus I can actually OC it past 500mgz.

At that point I'll finally be making good use of my PCI lock. Plus I'd get some ub3rly high FSB speeds

My RAM is coming in the mail. Since my NF7 can already do 233 with fully loose timings on my Ch-5 (so I know my RAM is the limiting factor). I am confident I can get it into the 260mgz range.

my .02

Well CH-5 is not too bad for AMD systerms. It is only intel systersm that have a prob with it, as i think that it does not like to run in 5:4. I would not go for pc3500 as it is the same chips that are in pc3200 and normally pc2700. 3700 sounds right.

doc6886 said:

I read that this would have a reverse effect and would cause a slower machine.

Perhaps these people with PC3200 are overclocking their RAM to be like PC3500?

Click to expand...

Where did you read this?

I picked up the notion that a higher FSB (IN SYNC) is more beneficial to an Intel system than an AMD one.


//added text to make it more clear

Even if it means running our memory clock speed well below the maximum feasible for a given memory, an Athlon XP system will ALWAYS exhibit best performance running the memory in sync with the FSB. Therefore, a 166FSB Athlon XP would run synchronously with DDR333/PC2700 (2*166) and give better performance than running with DDR400/PC3200, despite its numbers being bigger.

Click to expand...

This example shows running the memory at higher asynchronous speeds. Assume we have a Barton 2500+ which by default is running at a FSB of 333 MHz (166 MHz X 2) and we also have PC3200 memory which by default is running at 400 MHz. This is a typical scenario because many people think that faster memory running at 400 MHz, will speed up their system. Or they fail to disable the SPD or Auto setting in their bios. There is NO benefit at all derived from running your memory at a higher frequency (MHz) than your FSB on Athlon XP/Duron sytems. In actuality, doing so has a negative effect.

Click to expand...

That's assuming the fsb is still stock, unless I'm misreading it. What we're talking about is fsb and memory running in sync (not using dividers). What you quoted for example is like "fsb=166mhz, memory=200mhz". I was talking about "fsb=200mhz, memory=200mhz"


Anyways, for an AMD system ram and fsb should be the same. In an intel system using dividers could be beneficial.

If I might post a link to another forum -- You may want to scroll down about half way. It appears that not all good memory is gone if you want to spend as much for the memory (or more) than a board and CPU!!!

http://forums.extremeoverclocking.com/showthread.php?forumid=82&threadid=88320

ALSO

http://www.xtremesystems.org/forums/showthread.php?s=&threadid=27888

jlin453 is right, dividers are bad for AMD.

What you are stuck on is the PC rating, this only means what its rated to run at. PC3700 would most likely have terrible timings and for AMD you want as tight as possible. 11-2-2-2 is good.

Look for BH5 or 6 theres still some left, but don't worry too much about PC3200 or Pc3500 there the same, just the 3500 is garunteed to run at 217fsb.

I have Kingston KHX3000 and the famous Mushkin 3500, guess what, they run the same, 245fsb+ in my Infinity, just the Mushkin cost twice as much.

TDF.

I tried some PC4000.

I actually got into windows stable enough to run benchies . Sadly my crap stick gave me 50K in errors @ its rated voltage.

Raising the voltage to 2.9 got the errors down to 32K Im considering trying out another stick. Ive heard that Kingston has some occasional crap sticks.