[Asp]

I have a PC with an ASUS A7S333 mobo.
it claims compatibility with DDR333 RAM

I have a spare stick of 512MB DDR400 PC2300 RAM.

Is that compatible?
At least, is there any risk to the RAM and/or mobo in trying it?

This post has been edited by Asp: 22 June 2012 - 06:20 AM

[Tripredacus]

Typically, using a faster spec RAM in a slower speed isn't a problem. It just won't run at 400MHz, but 333MHz. Your BIOS might let you lock in the memory speeds too, you'll have to check it out. But the one problem is that I don't think you can use a 333MHz and 400MHz in Dual Channel.

[submix8c]

Gigabyte using DDR -
Insert 400 - set in BIOS to 333 - save - shut down <--as Tripredacus said (BIOS support)
Insert 333 - both running at 333

If put both in before BIOS SET, fails (tries to use 400)... (for said MoBo)

Point of note - I believe the CPU FSB speed has/had something to do with "default" DDR speeds... (can't remember)

JFYI/HTH

[pointertovoid]

I've already seen a mobo making Ram errors with Ddr400 but running fine with slower ones.

I believe to understand - but may be wrong - that its stupid Bios checks only the Ram speed, not the capability of the North bridge, and pretends to set a speed that the chipset cannot sustain.

Observations :
- Runs with Ddr333
- Doesn't boot with Ddr400. Memtest86+ detects some errors.
- Runs if on Ddr333 is added to the Ddr400.

[submix8c]

OK... let's clarify some things... Mobo's SOMETIMES require the RAM Speed to match the CPU FSB speeds. The one I noted above was due to the Processor FSB speed. Yes, it worked with faster RAM AFTER the RAM Speed was reduced to match. It wasn't the mismatch of RAM, it was what the FSB speed required.

@pointertovoid - check that CPU speed - bet it's a 333... Put a 400 CPU in it and watch it work with DDR400!

[puntoMX]

Even using 2 sticks of 333MHz DDR that don't have the exact timings will give you problems. All is stored in a chip on the PCB of the sticks that is called a SPD. Most motherboards will read the SPD from the first Memory Sloth so you would have the best success putting the slowest, lowest rated in DDR speed, stick in the first sloth. Set timings at 3 for CAS, RAS and C2R (CAS to RAS) in the BIOS. If you use windows use CPU-Z to read the SPD and see at what timings they run best. Use the highest numbers (highest latencies) to set those in the BIOS. CPU-Z should give you a range of options going from 200 DDR to 266, 333 and for the 400 DDR stick 400 too, logically. Note that sometimes CPU-Z will not show 333MHz but as it should be at 166MHz double data rate. Need more info? Ask .

[Asp]

I tried installing the DDR400, wasn't recognised by BIOS. It only saw the original 2x512 MB DDR333.

I couldn't see any relevant setting in BIOS I could tweak.

Guess I'll see if I can sell it or swap for something useful.

This post has been edited by Asp: 08 July 2012 - 01:13 AM

[puntoMX]

You might be using a high-density stick, most motherboards will not work with those. What model/brand stick is it?

[Asp]

puntoMX, on 09 July 2012 - 06:09 PM, said:

You might be using a high-density stick, most motherboards will not work with those. What model/brand stick is it?

Probably is high density, it only has chips on one side.

It's Samsung. label has:
PC3200-30331-Z 512 MB DR PC3200 CL3
M368L6523DUS-CCC 0549

Googlng that gives a datasheet:
DDR SDRAM Unbuffered Module 184pin Unbuffered Module based on 512Mb D-die with 64/72-bit Non ECC/ECC 66 TSOP-II with Pb-Free (RoHS compliant)
http://www.alldatash...523DUS-CCC.html
Most of which details are beyond me.

[Tripredacus]

Asp, on 10 July 2012 - 02:22 AM, said:

PC3200-30331-Z 512 MB DR PC3200 CL3

Your motherboard manual doesn't list that speed as being supported. Only these:

PC2700
PC2100
PC1600

Also says only 2 DIMMs support PC2700 (333MHz), if you add more it drops the memory speed to 266MHz.

I am looking at info on Page 26 of this PDF:
http://mtz01-a.stanf...uals/a7s333.pdf

The PDF has a modify lock, which also apparently doesn't let me copy (Ctrl+C) data off of it.

[Asp]

Tripredacus, on 10 July 2012 - 07:46 AM, said:

Asp, on 10 July 2012 - 02:22 AM, said:

PC3200-30331-Z 512 MB DR PC3200 CL3

Your motherboard manual doesn't list that speed as being supported. Only these:

PC2700
PC2100
PC1600

Also says only 2 DIMMs support PC2700 (333MHz), if you add more it drops the memory speed to 266MHz.

I am looking at info on Page 26 of this PDF:
http://mtz01-a.stanf...uals/a7s333.pdf

The PDF has a modify lock, which also apparently doesn't let me copy (Ctrl+C) data off of it.

Thanks.
Of course it doesn't officially support chips that probably weren't available when it was designed; in many cases they work anyway. But just not in mine, sadly.
I have the mobo manual, hadn't noticed it was locked. How silly. I have a PDF cracker if I need to use it.

It's not a big deal, I don't think I've ever run out of RAM while running any process, so it would just be bragging rights.

[dencorso]

I'd go for more ram than for faster FSB speed. PC3200 mean 3200 GB/s while PC2100 means 2100 GB/s... while the latter is a whopping 35% decrese in speed, I really doubt if you'd ever notice it, given the speeds of all the periferals, which are *so* much slower. Hence, with a single stick onboard, change "by SPD" to "Manual", and the grayed settngs will come to life, then set the bios advanced settings to the 3-3-3-8 and reboot. Does it boot OK? So far, so good. Then turn it off, and add the other stick. Cross your fingers and turn it on. Does it boot?

 A7S333.GIF (104.07K)
Number of downloads: 1

[puntoMX]

PC3200U-30331-Z is low density, but does this stick work in another PC?