O/C xp2600 ram question

[Wolfy]

Morning all, after reading the other post of the xp2500 o/c I have a question.

I'm at work so I don't have all the settings but basically I have:
xp2600
A7N8X
1gb twinmos 3200

I'm currently at 12.5*175. Memory is in sync. Vcore is at normal.

My question is if I tinker with the ram would that help to increase my overclock? What does "by spd" mean?

If I set the memory to by spd I get mem frequency at 200mhz displayed on the boot and the system won't work even tho I have it set at 175*12.5 but if I sync the memory I get mem freq at 175mhz and the system is fine.

What settings including timings should my ram be at and will it make a difference?

PS increasing the vcore of the cpu has no effect on stability and I haven't tinkered with the power setting on the ram.

Cheers for any advice and if it helps I can post up the entire lot of settings later if it's needed.

W


"Its only when you look at ants closely with a magnifying glass on a sunny day that you realise how often they burst into flames"

 

[ChipDeath]

All RAM sticks have a little bit of information about their ratings (speed and timings) embedded on a little chip on the PCB. Selecting 'By SPD' means rather than you setting the speed and timings, it'll try to set them automatically based on the information on the chip.

When overclocking, you should really set memory manually.

a 1:1 ratio will basically always be optimal (your overall system performance will probably be the same or better with RAM and FSB at 175Mhz than with FSB of 175 and RAM at 200)

You should try to find your highest FSB by slowly increasing the speed by 5Mhz or less at a time, and using a lower CPU multiplier (to rule out CPU speed being the cause of instability). When you hit limits with FSB you can try either relaxing memory timings, or increasing memory voltage. Both of these will help memory acheive higher frequency. It's safe to adjust memory V up to 2.8 or 2.9. Of course, you might have just hit a limitation of the chipset or CPU, but you should be able to get very near 200Mhz on that board - higher if it's a REV 2 or better.

If your memory is rated for DDR400 (PC3200) then it <i>must</i> be capable of 200Mhz, although that may require more relaxed timings than you've so far tried...

---
<font color=red>"Life is <i>not</i> like a box of chocolates. It's more like a jar of jalapeńos - what you do today might burn your a<b></b>ss tommorrow."

 

[ChipDeath]

forgot to add, if your CPU has a locked multiplier, then you'll be doing extremely well to get above 180Mhz FSB, and will probably require some fairly decent cooling (due to the VCore increase you'll have to start putting in)

If you have a XP mobile chip, you're laughing, but I think you would've stated so already.

---
<font color=red>"Life is <i>not</i> like a box of chocolates. It's more like a jar of jalapeńos - what you do today might burn your a<b></b>ss tommorrow."

 

[Wolfy]

ah that's informative. Answered a few questions I had in the back of my head.

Will tinker when I get home and see what happens.

What kind of settings for ram tho would be loose and then TOO loose cos I have no idea of how those timings work.

"Its only when you look at ants closely with a magnifying glass on a sunny day that you realise how often they burst into flames"

 

[ChipDeath]

Well, I don't know what your RAM is rated for, but you say it's PC3200. The most important one is CAS. this will most likely be 2.5 or 3 for that stuff, at 200Mhz (400 DDR).

the other 3 matter less, but something like 5-5-7 would be very relaxed.

I have some Corsair Low Latency stuff that will do 2-2-2-3 Timings at 200Mhz, but the odds of you getting anywhere near that are pretty low.

You can't really get too loose with the timings<b><font color=blue>*</font color=blue></b>, while you're experimenting with overclocking. The idea is to rule out as much as possible when focussing on one aspect, so using very loose memory timings helps ensure that's not what the problem is when your system becomes unstable. Then you eventually return to the timings and tighten them up when you're done with everything else.

Remember, it takes weeks (if not months) to find the 'optimum' settings for everything on a system like yours. Here's a 'rough plan' that I'd use when overclocking a rig like yours:

<b>1)</b> Find fastest FSB/Memory:
- Use a low CPU multiplier to rule out crashing due to too much CPU Mhz;
- Use relaxed memory timings;
- Increase by small amounts at a time, stress-test using progs like Prime95, 3dmark, and Sisoft Sandra for at least an hour at each setting - overnight if it's a 'final' setting;
When you hit problems, try increasing memory voltage to see if that helps - if not, then try small increase of chipset voltage, if the option's there (but you shouldn't need to do this while under 200Mhz).
<b>2)</b> try to get highest CPU clock possible:
- Increase CPU multiplier slowly;
- increase Vcore when errors are hit;
- Keep an eye on CPU temperatures. Anything over 55C is undesireable;
- Bear in mind that for highest CPU frequency you may need to reduce FSB by a little, as this gives you a little more control to fine-tune actual CPU speed;
- if you need anything over 1.7V and you should really get a better cooler than the stock one.
<b>3)</b> now you know (in theory) the highest speed your RAM/FSB can do, and the highest speed the CPU can do, figure out where the happy medium lies. for example, I had a 1700+- based system. I could do 205Mhz x 11 for ~2255Mhz, but couldn't get the chip to do 205x11.5 (~2357Mhz), but I <i>could</i> get stable at 11.5x200 = 2300Mhz, which was pretty much 'the sweet spot' for that system. Until the motherboard died, but ah well.
<b>4)</b>Now you have a 'final' FSB/memory speed, you can gradually tighten your memory timings again, until you find the lowest they can stably go. Again, more memory voltage can help here.

Another thing to bear in mind is that you may need a substantial Vcore increase for a comparatively small jump in speed - My old rig would run fine at 1.55V and 2255Mhz, but for 2300Mhz I needed 1.775V.

I didn't intend this post to turn into an overclocking guide, but ah well....

[EDIT]<font color=blue>* Well, I did actually have a board that refused to boot at CAS3, it wouldn't go any higher than 2.5... So if you hit problems try 2.5 instead of 3!</font color=blue>[/EDIT]

---
<font color=red>"Life is <i>not</i> like a box of chocolates. It's more like a jar of jalapeńos - what you do today might burn your a<b></b>ss tommorrow."<P ID="edit"><FONT SIZE=-1><EM>Edited by ChipDeath on 05/18/05 05:54 PM.</EM></FONT></P>

 

[Wolfy]

all good info, ill post up what I have at the mo and what I do and see what happens

"Its only when you look at ants closely with a magnifying glass on a sunny day that you realise how often they burst into flames"