Computer won't boot with 4Gb RAM, fine with 3

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majorbromly

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Jul 31, 2008
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Hey guys, this is my first post here but I've been lurking around for quite a while. I have a problem. I just had a new PC built for me, I had gone with 2 Gb of ram with the intention to upgrade later. Yesterday the ram came in I installed 2 more GB's and the computer would not boot. I removed one of them and I successfully made it into windows. Then I restarted again and the computer would not boot with my external HD attached. I'm honestly very confused here.

System is -

E8400@3ghz
2GB Ram@ 800 mhz (currently 3)
9800gtx (not that that matters)
Asus P5N-D moherboard
650 watt Corsair PSU
Vista 32

Can anyone explain why this is happening?
 
Do you mean my oldm sticks plus the one that may not work? No I haven't but I have the other of the new ones in there now and its working fine.
 
You most likely got a DOA stick of RAM. Send the kit back for a replacement. When I got a bad stick my PC wouldn't even give a POST code, and it sounds like you got the same thing happening.
 
If the second pair of sticks do not exactly match the original, you may have a problem. They need to be the same. Some motherboards are very sensitive to differences.

Assuming that all the sticks are the same, use memtest86+ to test out each stick individually.

Also use memtest to verify that a known good stick works properly in every slot on the mobo.

If all the sticks are good, then you may have to increase the ram voltage a bit. Look at the ram specs to see what the maximum is.
 
agree!!
 
I hate to tell you, but i have a P5n-e motherbaord and had the same problems that your having--When i contacted Asus regarding the problem, they told me that i was SOL cuz i didn't buy approved memory.

I was able to get my system to boot once or twice, but i had to manually set every setting for RAM in the bios.

If you check ASUS' forums, you will find many ppl having this problem.

See:
http://vip.asus.com/forum/view.aspx?id=20080712232916625&board_id=1&model=P5N-E+SLI&page=1&SLanguage=en-us

http://vip.asus.com/forum/view.aspx?id=20080716041534500&board_id=1&model=P5N-E+SLI&page=1&SLanguage=en-us

http://vip.asus.com/forum/view.aspx?id=20080714082048828&board_id=1&model=P5N-E+SLI&page=1&SLanguage=en-us


Sorry to be the bearer of bad news.


Ultimately i returned my P5N-e and picked up an EVGA 680i to replace it--havne't had a single problem.
 
What does anything in your posts have to do with the fact that hes running a 32 bit OS and a 32 bit OS wont recognize 4 gigs of RAM?
 
Fogartini, I was about to explicitly say to not mention that limitation. I figured the tomshardware peple are smarter than that, thanks for challenging my beliefs.

ANYWAY, All of the ram is identical, Corsair XMS2 1gb sticks. I will check on the voltage though, sounds easy enough to change.
 
You've run into a common issue (not mentioned above). Having 4 DIMMs installed at once is pushing the limits of current unbuffered DDR2 RAM technology. The control signals to the DIMMs get split among all of them, so having 4 installed means the signals to each are much weaker than with only 1 installed, causing errors. The better the motherboard design and the better the quality of the RAM, the less likely the problem, but once you have it, the only solution is to try raising the MCH (memory controller/northbridge) voltage a bit, perhaps 0.05V or 0.1V. This is NOT the DIMM/RAM voltage (which you should have already set to the spec voltage specified by the RAM manufacturer for your specific DIMM part number).
Good luck!
 
Where could I see my timings? The BIOS? The memory I bought is 4-4-4-12, the ones that I originally had may be 5-5-5-18. Would that cause this?
 
Not sure why timings matter here, but if you run CPU-Z, you should be able to see both current timings and the SPD settings stored in each module. If you didn't buy all 4 sticks at the same time, they are DEFINITELY NOT identical, even if they have the same model number. Memory manufacturers make minor-to-major changes in their models as often as weekly.
No, different timings would not cause this, as the MB should just default to the slowest timings.
 
To majorbromly:

In your original post you mentioned that you had a new PC built. Did you install Vista with SP1? The reason I say this is that the original Vista DVD would not let you boot into Windows if you had more than 3Gb of memory. MS later released a patch for this which is now included in SP1. Personally, I install vista with 2GB and then install SP1. Once that is done I install the remaining 2Gb of memory.

http://support.microsoft.com/kb/929777

I have an Asus P5N-E SLI board and I have 4x1Gb Corsair XMS RAM, SLI certified with 4-4-4-12 timings. I haven't had any problems with them. I had bought 2 in jan 2006 and bough 2 more earlier this year. I don't think the difference in your memory timings would cause a problem. But I am not sure about this. I though a faster 4-4-4-12 memory would automatically underclock to match the slower 5-5-5-18 memory.

I would try installing Vista with just 2Gb and see if installing SP1 fixes the problem. Just make sure you're using the memory with the same timings. You should also try the other options listed in the other posts. It is just time consuming and you just need to narrow down your options on what might be causing the problem. Good Luck!!

To Fogartini:

Your post about a 32bit OS is somewhat correct, however that is not the case here. Regardless of how much memory a 32bit OS will recognize, it will still allow you to boot into windows. It just won't use more than it can recognize. Also, 3Gb is not the maximum a 32bit OS can recognize. The memory allocation for RAM is done last and depends on how much other hardware have used up. A large majority is used up by the GPU. For Ex. if you use a GPU with 64MB Ram then your computer will most likely be able to recognize more than 3Gb (Which you said only a 64bit OS can recognize). If the OP decides to run two Nvidia GT 280 cards in SLI, he would be using about 2Gb for his video cards, then the OS would only be able to recognize less than 2GB.

 

Good job Mondoman. The best explanation I have seen of the 4 stick issue.

Corsair 5-5-5-18 memory is spec'ed at 1.9v. The 4-4-4-12 memory needs 2.1v to run at that speed. I think all the memory you install gets the same voltage; you can't mix. Obviously it partly works because you can get 3 sticks running. Corsair recommends a 4gb kit to be certain that all the memory is exactly the same. They have good customer support. Open up an incident with them, maybe they can help you out.

To separate out the OS issue, test with memtest until you get all 4 sticks running. It will be faster than booting windows anyway.

---good luck---
 
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