RAM runs slow

[chris_uk_83]

I have a minor irritation with my RAM: on bootup I'm told that there is 2Gb running at 100MHz. Now when I only had 1Gb it ran at 200MHz. Does anyone know any ways of speeding it back up again? If I remove 1Gb it speeds up again.

It's DDR400 in 2 x 512Mb and 1 x 1Gb sticks, none of which actually match precisely (which I realise isn't ideal).

My mobo is an Epox 8NPAJ socket 754 running nForce 4.

Like I said, this is only an irritation, but it'd be nice to make it run at the speed it's designed for.

[alman9898]

Whats your FSB speed? Also you should probably be able to adjust in your BIOS, although I don't know if you should boost it up 100MHz in one try.

[sdjenkyn]

your ram is only going to run as fast as your slowest stick. Are you sure they are all ddr 400. Have you run cpu-z? Gives pretty accurate feedback and its freeware.

[kshcshbash]

Get Linux and get some stats from there...


^^ That was a useless post:
I think you're going to have to OC a bit, they have to run at the same frequency.

[chris_uk_83]

your ram is only going to run as fast as your slowest stick. Are you sure they are all ddr 400. Have you run cpu-z? Gives pretty accurate feedback and its freeware.

Yeah, they're definately all DDR 400 sticks, though the CAS timings may vary between them. I might try out that cpu z thing, but I'm not installing Linux just to get stats because first: I don't know how, second: I don't know how to work Linuz once it's installed and third: I can't be bothered learning because it's not that important.

[Erik]

Sounds like you BIOS falls back to it's default 100MHz FSB for some reason.
Probably something to do with the SPD on your new memory module (The SPD is a small chip on your memory card that tells your computer what kind of memory it is) .

Does your core clock still run at full speed?

Use cpuz to check:
-core speed (cpu tab)
-multiplier (cpu tab)
-memory frequency (memory tab)
-SPD memory timing of each module. (SPD tab).

You'll probably have to manually set your FSB speed in BIOS.
But make sure you set your multiplier to it's correct setting at the same time, or else your computer might not boot.

Also make sure you know how to reset your BIOS settings in case your computer doesn't boot anymore. (this probably involves removing a battery or moving a jumper)
You might also want to record all your BIOS setting so you know how to restore them in case of a BIOS setting reset.

[chris_uk_83]

I'm not massively sure what to do with multipliers to set the FSB speed. I've seen them and I've got a vague idea of what they do, but I've never messed with them before out of fear of frying my PC. Is there a simple equation to follow when altering these things?

[Echbart]

Could you post screenshot of CPU-Z ( CPU and Memory menu ).

[Erik]

I'm not massively sure what to do with multipliers to set the FSB speed. I've seen them and I've got a vague idea of what they do, but I've never messed with them before out of fear of frying my PC. Is there a simple equation to follow when altering these things?

Yes:
FSB speed x cpu multiplier = core speed.
FSB speed x memory multiplier = memory speed. (I'm not sure, but I think AMD system always have a fixed memory multiplier of "1", so you can't change the memory speed without changing the FSB speed)

So if you double the FSB frequency you must cut the multiplier in half to keep your processor running at the same speed.

for example
100Mhz x 20 = 2Ghz.
200Mhz x 10 = 2Ghz.

[chris_uk_83]

I will when I've downloaded it and run it. I'm at work at the mo, so it'll have to wait until 5 (GMT).

[chris_uk_83]

Right, some screenshots for you:

CPU:
http://www.chrisuk83.plus.com/Images/cpu.jpg
Memory:
http://www.chrisuk83.plus.com/Images/memory.jpg
Memory slot 1:
http://www.chrisuk83.plus.com/Images/slot1.jpg
Memory slot 2:
http://www.chrisuk83.plus.com/Images/slot2.jpg
Memory slot 3:
http://www.chrisuk83.plus.com/Images/slot3.jpg

Thanks for helping everyone!

[Erik]

OK, I think I know what happened:

The 1GB stick in slot 3 has a SPD CAS latency of 3 clocks.
The other two sticks have a SPD CAS latency of 2.5 clocks.

Your entire memory is running at CAS 2.5, which is too fast for your 1GB stick.
But rather than increasing the CAS latency to 3 (which would be the correct way of dealing with the different CAS latencies), your system has reduced the memory speed to 100MHz.
The lower memory frequency makes it possible for your CAS 3 stick to run at CAS 2.5, but DDR-400/CAS 3 is a lot better than DDR-200/CAS 2.5, so this isn't what you want.

Your FSB is running at 200MHz, which is correct, and your CPU core speed runs at 11xFSB=2.2Ghz, which I think is also correct.

Try this:
In BIOS, increase CAS latency from 2.5 to 3.
Then reboot and use cpuz to check if the problem is solved.

If this didn't solve your problem go back to BIOS and set FSB:dRAM multiplier from 1:0.5 (or CPU/22) to 1:1 (or CPU/11).

note that the FSB:dRAM multiplier works just like you FSB:CPU multiplier:
FSB x CPU-multiplier = CPU core speed.
FSB x DRAM-multiplier = memory speed.


edit:
you might also have to increase:
CAS to RAS latency from 2 to 4.
RAS precharge from 2 to 4.
Cycle time (aka TRAS) from 5 to 8.
In short: you need to set all the latencies (CAS, CAS to RAS, RAS precharge and cycle time) to the largest (ie: worst) figure of all 3 memory sticks.

[chris_uk_83]

Nice one Erik, problem solved. I dropped the CAS latency to 3 and nothing happened. Then I went hunting for the FSB:dRAM multiplier and couldn't find it. What I did find was an option to tell the motherboard what RAM it had installed instead of letting it choose. I forced it to be DDR400 (200MHz) and now it runs that fast! Rep for helping

EDIT: when I can, I've run out of rep giving points for you for the moment.