XP won't boot after installing new memory

[yusoffb01]

My motherboard's model is Biostar P4m890 (uses via chipset)
Accoding to the website this mobo with 2 ram slots support 2gb each max 533mhz RAM. I had 1.5gb (1gb + 512mb). So i bought 2gb ddr2 800mhz because from what I know, there is option in BIOS to change speed to 533mhz. After replacing the 512mb with 2gb ram, the computer passes POST (means ram seated properly) and goes on to load windows XP. However while the blue bar is moving, all of a sudden for no reason, the loading would stop and the computer reboot by itself.

I have tried placing the 2gb ram in another slot and still same problem-won't boot. However once I DID manage to boot and go to windows xp. According to task manager i only had 1gb ram when in fact i have 3gb inside. I checked using CPU-Z, sure enough it shows 2 different ram there and detects as 3GB ram. I tried to reclaim the missing 2gb ram by going to msconfig under book>advanced option>max memory>4096. However after i restart, win xp still fails to recognize the 2gb and shows as one. under max memory in msconfig, it reverts back to 1023. Also in BIOS only shows 1gb.

Then i removed 1gb ram to see if winxp can boot with the 2gb ram alone. It couldnt. It would just reboot over and over again.

Frustrated after wasting 1hr with this ****, I put back 1gb ram and 512mb ram and winxp works no matter which slot i put them to..

So what do you think can be the problem here?
1)Non-working RAM (doesn't POST with the ram being alone inside)?
2)Mobo doesnt support 2gb density ram?
3)Mobo doesnt support that 800mhz speed? (but it can force ram to slow down in BIOS right?)

Do help me please... I wasted $29 on the RAM.

 

[gamerk316]

I'll check up on the mobo, but i'd run memtest86 on the "bad" ram in the meantime...

 

[MaDMagik]

Hi there,

You have mixed 2 differently rated memory sticks, be aware that same values will be applied to both sticks, so for example: if your 533 ram is rated at 1.8v and the new one is rated at 2.1, the new might not work on 1.8, even at only 533mhz. The timings are probably lower for the 533 one that the 800 one cant handle. You cant have different values for each stick, so you shouldnt mix different ram in genereal, because you have to run one under its spec or the other one over its spec. When you tried booting with 2gb stick alone, did you go to bios and checked/adjusted its settings?

 

[yusoffb01]

on 2gb alone, wouldn't post. Maybe ram doesnt work?
Both rated 1.8v

 

[yusoffb01]

Got replacement ram. It works now but can't mix and match new memory 800mhz with old one. Even when i set bios settings to force it operate at 533mhz (old memory speed). XP loads with weird graphics. Im guessing its timing problem. Faster ram tighter timings then slower ram. Can anyone help? In bios idk what to change the settings to.
According to cpuz at 266mhz it runs at this timing
CAS LATENCY-4
tRCD-4
tRAS-12
cr-2T

http://www.pcstats.com/articleimages/200612/biostarP4M890M7_BIOS1.jpg

which should i change my bios looks like that.

 

[yusoffb01]

ok problem solved! i manually change speed to 266mhz (533 effective)
CAS Latency-4
Bank interleave- disable
Trp (precharge to active)- 4
TRAS- 12
TRCD- 4
TRFC- 37
TRAD- 3

I had no idea what to change those values to and at first try they worked! GOod enough for me...

I mixed 1gb (rated 533) with 2gb (rated 800mhz) and both work at manual speed and timing. Auto timing doesn't work because i guess the mobo assign different timing to each RAM.
Thanks for help ppl!