Which is better....

Mutant_Fruit

I have 2 sticks of ram, a 256mb 266mhz chip; and a 512mb 400mhz chip.

Should i either:

A) Take out the slow one and bump up the ram speed to 400mhz
OR
Leave them both in and run them both at 266mhz?

I think my 266mhz ram chip can be run at 333mhz safely, but i don't know how to check ram overclock stability. If someone could recommend me the approprite program to test ram overclock, i'll see what i can do with regards to leaving them both in, and running at above 266mhz

LastIrishMonkey

id say leave the 2 in bit of a guess but i have heard of that before and i think its best to leave em in !:dunno:

Dempsey

Option A

Col_Loki

Umm depends on what system your running.....

If its an AMD one then dual DDR means nothing really (2-5% performance gain) so go with the 400mhz Ram, if its an Intel with Dual DDR then the dual option should be the best performance wise.

Testing Ram overclock, i take it you mean stability?? Then Memtest or Prime95 should do the trick. For a performance idea try SiSandra's mem benchmark....... will give you an indication.

vibe666

unless you're a very heavy gamer you're not likely to use more than 512mb of ram anyway, so the extra would be useless, and since it's going to drag your speed down, you're better off without.

IMHO

Big Chief

i would go with option A (then buy more 400mhz stuff and sell on the 266 stuff..)

but thats just me

Col_Loki

i would go with option A (then buy more 400mhz stuff and sell on the 266 stuff..)

Sounds like the best option actually, thought they were 2x256mb ram modules......

Mutant_Fruit

So what kinda real-life performance gains would i get out of running jjust the 512mb of 400mhz stuff?

SantaHoe

Originally posted by Mutant_Fruit
So what kinda real-life performance gains would i get out of running jjust the 512mb of 400mhz stuff?

Why don't you try it, do a few benchmarks and let us know?

Mutant_Fruit

i just did a big ram overclock.

I set my ram to 333mhz (is that PC2700?) speeds instead of 266mhz speeds in the bios, and that combined with my FSB overclock brings that ram up to about 360mhz.

I an Memtest for 30 mins, and it was perfect. I then tried lowering the CAS latency from 2.5 to 2.0, and that also worked perfectly in memtest. When i reduced it to 1.5 however, i just got lists of errors in memtest, so i moved it backl to 2.0. I could probably get another few mhz increase on my FSB if i wanted.

Those settings give me a bandwidth of about 2000mb/sec in sisoft.

The question now is, what benefits will i get if i now remove the 256mb module, and instead try and overclock just the 400mhz one. I'd say i can get a max of 450mhz on it, no more. In that case, which would be better, 768mb@360mhz or 512mb@450mhz.

I know benchmarks will say that the second option is better, but is losing 256mb ram worth the increase?

Col_Loki

What system are you running ??

That memory benchmark isint great to be honest, should be scoring higher with Pc2700 . Tell us what system you have and what ram & FSB the system actually supports.....

Mutant_Fruit

OK.... here's the specs (as close as i can remember)

All mhz are at default values...

AMD Athlon XP 1800+ (266mhz FSB)
Ram: 1 stick of 256mb@266mhz (pc2100?)
1 Stick of 512mb@400mhz (PC3200 i believe)
Windows XP SP1
Mobo: Epox 8K9AI, i beliebve its KT400 chipset or something similar.

I currently have the FSB overclocked from 133 to 142, and it's dead stable. (that makes processor run at 1.67ghz instead of 1.53). The ram i have set to 333mhz speeds (PC2700?), and with that overclock the effective speed is supposed to be about 350-360mhz. The chips are in the second and third bank, or it could be first and second. One of the banks is blocked by my heatsink, but with a bit of effort, i could unblock it if it would help..

I think the mobo FSB maxs out at about 250, and the highest speed i can set the ram too is 400mhz (PC3200).

Col_Loki

Ok with an athlon system your Ram runs at the same speed as your FSB is set to ........ if you set your ram to 400mhz etc you will see NO performance gains. On the AMD boards you need to set the Memory to run InSync with the CPU FSB (CPU interface enabled) for best results (in my experience).

Your Ram isint really running that fast , its all dependant on your motherboard really. You should be able to set it to 166mhz (adjust your CPU multiplier down accordingly) . Setting FSB between "jumps" can cause hard drive corruption or GFX failure because your board uses dividers. You wont hit 200mhz FSB to use the faster Ram , best you can hope for is 170-180 i think.........

[edit] theres not a chance in hell of that mobo getting close to 250mhz FSB (even though it might be an option). Give it a go with only the Pc3200 ram and low CPU multiplier and see how you get on.

[edit] Up to 180mhz using the 166mhz divider will run your hard drives & GFX at an overclocked spped but i havent heard of any problems. Over 180mhz and your asking for trouble (although i dont think you'll get there anyway).

Mutant_Fruit

my athlon is locked, so i can't change the multiplier on it unfortunately... unless you know an easy workaround, it looks like i'm screwed.

One thing though... my motherboard allows me to set my fsb to whatever, 133mhz for my processor. But i can then set my ram to 333 or 400mhz, and on the bios boot screen it shows up as 400mhz. Is this ram really running at 266, the same as the processor?

Col_Loki

Do a benchmark of your ram running at the FSB speed and when its set to 333mhz or 400mhz........ the scores should be the exact same give or take a tiny ammount.

Your best option is to overclock using your FSB (only option in fact), means you will be overclocking your CPU also but this should be well and trully able for it.

ie your FSB at 180mhz ish, gives you much better memory scores & your CPU running @ 2ghz ish..... You might have to adjust the Vcore a small bit (wont be much if any).

Mutant_Fruit

I re-did the benchmark and compared it to some 266mhz ram, and it was exactly the same (give or take 100 points), so it looks like the increased FSB and setting to 333mhz actually did nothing. Argh.

I'll give FSB overclocking another shot now, but i think before i couldn't get over about 148, but that was probably due to the slow ram. I'll take out the 256mb of slow stuff, and see what overclock i can get with just the 512.

Mutant_Fruit

Nope, i can't overclock the FSB more than about 18mhz before it locks up. Ah well, at this rate i might as well just leave both in, as there seems to be no way i can get the 400mhz one running at 400mhz. What i pity i splashed out a bit extra on getting it.

Col_Loki

You really need to watch the fact that your board doesent have an AGP / PCI lock....... i would take out the slower ram and pop the FSB up to 166mhz and start upping it from there.

Sell the slower ram its pretty much uselss in your case. Make sure your CPU isint holding you back by upping the voltage a little (very un-lightly it will hold you back).

Your AGP speed should be 66mhz, PCI - 33mhz

so........ for an FSB or 133mhz the divider is set to 4:2:1 ....... 133mhz:66mhz:33mhz
when you get to 150mhz FSB the board will still be using the same divider so your AGP will be at 75mhz , PCI @ 37.5mhz.......... ie overclocked.

Thats why upping the FSB between dividers is dodgy. 133-145 (prob up to 150) , 166-180 is pretty safe but still slightly overclocking your hard drives, GFX card etc.

Hope i explained that some bit ok for ya..... your board should do 166mhz FSB, so should your ram , so should your CPU........ pop it up to 166mhz FSB and then try to stabilise it?

Mutant_Fruit

Ok, i flicked it straight up to 166, with just the 400mhz ram chip in it. It wouldn;t boot.

It then reset to 133mhz, so i decided to slow the ram and increase the CAS latency to see if that would help, still no go, it rebooted back to 133 again.

So, i re-applied the same changes to the ram, and bumped up the voltage to 1.850 (an increase of .100 or .150) and tried booting at 166mhz. Still no go.

I think this is just a lost cause. The next time i buy some hardware, i'll invesitgate it's overclocking abilities first.

Col_Loki

Did you try setting the dividers to the next up ?? ie 5:?:1 or something like that??

Thats the last step you should try before giving up :rolleyes: , really should work!!

[edit] Doh, just looked at your Vcore....an increase of .1 to bring it to 1.85v means the stock is 1.75v = palli core CPU.
I pressumed you just bought a new locked CPU.

Ouch palli's just dont overclock well at all and run very very hot......... looks bad mate!!

Mutant_Fruit

Damn, sounds bad alright. Looks like i'm screwed. I didn;t know it was a palli core (i don;t actually know what that means...) but no, it doesn't seem to overclock well at all. I got this second hand, so i thought it was a standard throughbred. Obviously i was wrong.

Thanks for the help anyway.

cheradenine

Yeah my last machine was a palomino 2000xp and it was a pretty miserable overclocker , in addition to getting extremely hot after only a slight fsb increase, the thoroughbreds overclock far better around that level.

Col_Loki

Yea some of the "palimino" cores were among the hottest chips around. They require high Vcore voltage to stay on stock speeds, which is bad.

To put it into perspective.............

An Xp2500+ mobile requires 1.45v Vcore to remain toatlly stable (prob with very little cooling) .
A palimino core Xp1800+ requires 1.75v to remain totally stable (and required more cooling)

Its not the chip for overclocking, and neither is your motherboard im affraid, put the two toghter and you have a poor overclocking system im affraid. Your ram may come in handy if you intend on upgrading but at the min its pretty useless im afraid (over 150mhz FSB anyway - 300mhz DDR). A €170 sih upgrade would give you an Xp3200+ and running your memory at 400mhz - ie an Xp2500+ boxed & Abit NF7.......... but other than that your not going to get much more than stock from your machine im afraid!!