Desktop won't boot with two sticks of 2 GB RAM installed

I am a disabled retired mechanic. I work on computers to have something to do with my time.

My problem is that the desktop I am now working on won’t boot when two sticks of 2 GB ram is installed. It will boot with two GB in DIMM 1 or DIMM 2 but not when both DIMM’s are populated.

The desktop is a Dell Optiplex 520 that I was given and wouldn’t boot. I found the one stick of ram bad. The desktop came with XP but I installed W7 Pro x64 to see if the motherboard would run W7. It had 2 GB bad ram and I replaced the ram with a 2 GB stick. But I wanted 4 GB ram and I installed another stick and the problem started. The desktop boots past BIOS and when the Windows icon assenbles as a whole the computer stops booting and will do nothing. I have to use the power button to turn off the desktop.

Run 2 GB, well I would but I have a processor ordered and when I get the processor installed I am planning on installing W10 Pro v. 1909 and want 4 GB"s of ram. Also, manual says that the board will handle max 4 GB RAM

Anyone have any idea why the desktop won’t boot with 4 GB’s RAM. Thanks.

Are the two 2GB DIMMs identical? If they are different it could be that the timings are not suitable for one of them, especially if the CPU or chipset switches to dual channel mode anyway. E.g. if one is DDR266 CL2 and the other is DDR400 CL3 and the board switches to DDR400 CL3 the DDR266 DIMM will be running out of its specification (with 200 MHz instead of the required 133 MHz).
Check if there’s an option called “Memory hole remapping” or similar, enable it if possible.
Other possible causes are PSU, BIOS issues (ensure newest is installed).

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Thanks Oinker for the reply. Yes they are identiacl .

Problem solved. I was reading up on ram and it was said that sometimes an older BIOS version can cause ram problems. So I shut down my computer, rebooted, entered BIOS and saw I had an older BIOS. I updated the BIOS to the latest version and now the desktop boots with two 2 GB sticks of ram installed. Now I have the 4 GB dual channel ram that I wanted when I get the new processor and install it, and install W10,

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Hence I said you should ensure you’ve the newest BIOS installed. :smiley:

Good you solved it.

Well I’ll be. You post is probably were I saw what I was talking about. Anyway it got into my mind and led me to update the BIOS. Just wait, when you get to be 69 and senile you’ll do stuff like that too. :smiley: :rofl: :sunglasses: Thanks Oinker.

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Hey Oinker. How about doing me a favor. I have taught myself to work on computer, with help from people that know more than me.

So, question. The computer came from the factory supporting a maxium of 4 GB ram, along with the BIOS version that was in the computer when I updated. So, why wouldn’t the BIOS that Dell installed support the 4 GB ram it said the computer would support. Thanks.

Difficult to say, but sometimes it’s simply a BIOS bug. Could also be that certain RAM chips didn’t exist at the time of the BIOS version the computer was delivered with, so that problems with a new size of RAM chips had to be adressed with a BIOS update. The maximum of RAM supported is usually just determined by the number of RAM slots and the maximum size of the available DIMMs, e.g. if the board has two DIMM slots and the maximum size of a DIMM is 2 GB the maximum of RAM supported would be 4 GB, with four DIMM slots it’d be 8 GB. Regarding your problem it could be that a different type of 2 GB DIMMs would’ve worked just fine with the BIOS installed, who knows, but that particular issue with the RAMs you use obviously has been adressed with a BIOS update.

Thanks Oinker. I can repair computers, build computers but this ram thing is something I haven’t yet wrapped my brain around the way I wish… What you said makes sense and gives me something to think about.