Different CAS RAM in same machine???

[pritsey]

Hi all,

Got some more RAM for XMAS to put into my Shuttle.

Before XMAS I has 256MB of CAS 2.5 PC3200 RAM. Could run it at 200 FSB with my Barton XP2500 no probs at all.

XMAS day I open up my RAM to find that i have been givewn 256MB of PC3200 but this time it's CAS 3 and also not the same manufacturer.

Well, it works fine at 166 (333) FSB but not any higher. If I try and run it higher then the BIOS POST reports an XP1100 and not a XP2500. I can increase the multiplier without any issues arising. At the moment I'm running the normal FSB of 166 (333) with a multiplier of 13 instead of 11. On POST it now says XP3000. It runs fine so no probs.

Basically, am I not able to run at 200 FSB due to the different CAS ratings on the RAM?

Oh, BTW it's a Shuttle SN45G with Nforce2 ultra 400 chipset.

Cheers all.

[streetster]

can you run it at 200mhz at cas3 ? if not i'd send it back and try to get a cas2.5 (or cas2) stick...

mark

[SilentDeath]

if it wont work at 200mhz with 7-3-3-3 then send the new stick back. tbh though anything over 7-3-3-2.5 is more than pointless as it makes v little diffence.
at 7-3-3-3 you might be able to use higher than 200 though..

ram is a lot more fussy about what timings you put it at than the mhz you put it at.
try inc vdimm voltge to 2.8 or somewthing and it might work at 200/7-3-3-2.5 or 2

[pritsey]

I'll try each stick independantly and also with the different timings, then I'll post again.

Cheers for the help so far.

[shamus21]

pritsey can you tell us what the manufacturer is.

[pritsey]

I'll get the manufacturers in a moment when I open up the shuttle. They were both bought as Ebuyer extra value. However, I'm pretty sure that they're branded.

[pritsey]

Ok.....

The CAS 2.5 stick is an A data, possible K data, the symbol was a bit funny. The CAS 3 stick is made by Elixor.

After testing.....here goes:

The old 2.5 stick works at 200 FSB is memory slot 1 no problems. Won't in slot 2 with nothing in slot 1 though.

The new CAS 3 stick works at 200 FSB is slot 1 but not slot 2, same as the other stick of RAM.

So at least I know that both sticks do actually work at 200 as they're supposed to.

Now I was a bit worried that it could be the motherboard. But it could just be that the motherboard doesn't like having a stick of RAM in slot 2 with nothing in slot 1. Maybe it's that dual channel Nforce 2 thing????

I've tried both sticks in together agin and swapped their positions (slot 1 & 2) and they refuse to wrk together at 200 FSB. Looks like I'll have to buy a matched pair of RAM sticks.

I tried to change the timings manually but it didn't help. I also tried to change the vdimm voltages too - again nothing.

In case you wanted to know what the standard settings were -

Vdimm - 2.52V
CPU voltage - 1.68V
memory timings - 7 - 3 - 3 - 2.5

It also look slike the maximum multiplier that I can use is 13 with a 166 FSB. Anything higher and Windows refuses to boot. Below is a pic when both sticks are in and the FSB is set to 200 witha 10 multiplier:



Weird........

[prayer] Please don't be the motherboard [/prayer]

Cheers all!

[streetster]

maybe your fsb is at 100 (ie 200), rather than 200 (ie 400 ram speed), and your cpu is multiplier locked?

are you saying you cant stick both sticks in there at cas3 and run it at 200mhz fsb?

mark

[pritsey]

The CPU isn't locked as I can run it at different multipliers (max 13 though).

It's also not running at 100MHz FSB as I've had it running at 200.

The CPU is a Barton XP2500. As I posted above, both sticks will happily do 200 (400) FSB independantly but together they're a bit of an arse!

It is a bit strange though......

[pritsey]

Actually Streetster, having just had 5 mins to think about it, you may be correct. The pic above shows 200MHz FSB, and it should say 400MHz when running at 200 (400). At standard frequencies it shows 333MHz so why is it going wrong?

[3Dfx]

CAS3 RAM probably wont run at CAS (Column Access Strobe) 2.5 ... so therefore clock ya CAS2.5 to 3 and run it at as high as u can... it'll only run at the speed of ya weakest link... the CAS3 RAM.

[SilentDeath]

stick the vdimm upto 2.6 or 2.7 and you should be able to run both at 200/400 and maybe even cas2.5 though they probly prefer cas3.

test with memtest86

[pritsey]

Well, I just tried upping the FSB to 200 (400) and it's working! I had to increse the voltage on the RAM to 2.7, then I tried with 'optimal' settings and it refused to boot. Then back into BIOS and changed the voltage to 2.6 and all seems well. POST reports an XP2000 but it's running stable at 200 x 10.

Cheers guys!

[blockers]

Is it possible the RAM is crap?

I have some generic RAM, from aria (pc2700) and that wont go above 145fsb ish...

Will

[pritsey]

Well, the RAM could be crap, but after testing I found that it did what it said it would - ie it worked at 200MHz. I'm guessing that in my situation it's that the 2 sticks of RAM that I have or either incompatible or that my motherboard doesn't particulaly like the RAM. I have heard other people saying that their Shuttle only likes branded RAM. I suppose you get what you pay for....