Extra RAM destroys my PSU!

June 23, 2009 8:31 AM

I installed new RAM, and blew my power supply. Now, after installing a better power supply, the same symptoms which led to the broken power supply are happening again. What is going on?

I recently ordered a pair of these to upgrade my computer from 2GB RAM to 6GB, after installing Windows 7 64-bit. This is what Crucial told me is compatible with my Intel DG965RY motherboard.

After turning the computer back on, I noticed that Windows hung on startup. I shut it down and ran Memtest86+, but that ran very slowly (although didn't show any errors).

I then restarted, and after a couple of beeps from the mobo, the computer wouldn't turn on. SO I ordered a new, more powerful PSU.
For comparison, the model I had originally was this one. It is 430W and has a max current on 22A across the +3.3V rail (I think this is important if you want to add more RAM, right?)

The one I have now is this one. This is 600W and has 35A across the +3.3V rail.

Just to be safe, I sent the RAM back and bought exactly the same type again. I installed it, and then ran both Memtest86+ and Windows Memory Diagnostic before attempting to boot Windows. They both showed no errors. When I then tried to boot Windows my computer froze! Scared of blowing my PSU again, I shut it down and removed the RAM. It now seems to work fine.

What can I do? Surely my power supply is more than adequate for some RAM?

Thanks in advance

posted by edbyford to computers & internet (10 comments total)

Why do you assume it's a PSU error in the first place? The beeps suggest that it's failing on POST, which means the problem could be on the RAM or CPU level as well. I'd say you probably got some defective RAM.
posted by nasreddin at 8:36 AM on June 23

Oh, just noticed that you had sent it back. It could be that your motherboard is hosed--sometimes these kinds of problems don't appear until you stress it (for instance, by adding more RAM).
posted by nasreddin at 8:39 AM on June 23

What other components do you have in the system?

If you remove the new RAM modules does the computer boot correctly?

Do you have the latest BIOS for your motherboard? The release notes indicate some issues with higher amounts of RAM.
posted by borkencode at 8:39 AM on June 23

According to this page...

DDR2 Power Dissipation

Power Dissipation for reference only.
A DDR DIMM needs 5.4 watts, a DDR2 DIMM needs 4.4 watts and a DDR2 FB-DIMM needs 10.4 watts

Your 400 watt power supply was more than sufficient to support the ~10 watts of power your memory needed. More likely there is a bios issue (as borkencode suggests), or something more insidious such as the board not supporting higher performance memory for some odd reason.

Additionally -- there are numerous posts on the intarwebs about the DG965RY not liking mismatched memory sticks, and generally running slow with certain types of memory.

Do you really need 6gb? Does it work ok with just 4gb?
posted by SirStan at 8:55 AM on June 23

Thanks for the quick reply guys!

@SirStan, interesting what you say about the mobo not liking mismatched memory. I don't really need 6GB, just thought it might be fun!

So, in summary, I should try both:
- upgrading the BIOS
- running with 4GB

before I give up.

However, why did my computer fail to turn on? Surely something that severe can't be due to a simple BIOS bug, or my board being incompatible with the memory?
posted by edbyford at 9:02 AM on June 23

I'm usually the first person to point to PSU failures -- the crappy no-name PSUs most people use are really horrible in terms of reliability and are an obvious first guess -- but nothing you're describing in the first place sounds like you had or now have a PSU problem. What you have is either bad RAM or mismatched sticks.
posted by majick at 9:08 AM on June 23

You've completely jacked up the chain of troubleshooting you should have followed.

It's impossible to say now definitively what was the problem where, or what's going on now.

You should start from scratch, seeing if you can get your system to POST with one stick of ram, then swap it out for another stick, and so on until you verify the ram is working in total.

You should follow your mother board's documentation for where to place the ram for post - sometimes it matters.

Also, if you can get into BIOS you should re-load your "fail-safe" or factory default settings for the purpose of trouble shooting, however disable any splash screen or logo that may obscure system POST information.

why did my computer fail to turn on?

It's impossible to say. However, just because the system doesn't POST or "turn on" doesn't immediately mean that the PSU is bad. Indeed, modern PSUs and motherboards being what they are, they system may have needed an complete power cycle - where you disconnect the PSU from the motherboard, and unplug it from the wall, and wait a few minutes.
posted by wfrgms at 9:30 AM on June 23

Oh, and just to clarify, don't get caught up in the OS or issues there... get the system to post reliably first then worry about your OS.

Also, you should only upgrade your BIOS if the system is POSTing reliably with the minimum amount of ram. (but you should upgrade)
posted by wfrgms at 9:33 AM on June 23

Also, you need to delete some of your tags in this post. "Seven" is not a useful tag. You should run together words. So, instead of "Windows 7" you should use "Windows7"... instead of "power supply failure" you should use "powersupplyfailure"

Of course, this question really has nothing to do with Windows 7 (or any OS) so you probably should delete those all together for the benefit of other MeFis searching for accurate information.
posted by wfrgms at 9:36 AM on June 23

After following the link given by SirStan, I found out that the BIOS version 1687 which I was running had a bug in it which caused the system to run very slowly. I flashed the BIOS to 1761 and now everything is solved!

Thanks for all your help guys!
posted by edbyford at 9:54 AM on June 23