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phaedrus69
Jan 2, 2009, 09:24 AM
Replaced RAM in my Dell Dimension 4700. Went from 2 256 MB modules to 4 1GB modules. Tried them all at once at first but got an Intel screen, and no Windows boot. Installed the originals and everything worked fine -so no damage to mother. Installed 2 of the new in slots 1 & 2, & worked. F2 setup showed 2 GB, & control pnl showed 2 GB. Installed a 3rd in slot 3, with the same result -F2 setup showed 3 & so did control pnl. When I installed the 4th though, F2 setup showed 4GB, but my control pnl is only showing 3GB. The computer is listed as being able to handle 4GB, so I don't understand. My thoughts are maybe, because I installed to the first time, then the 3rd, & then the 4th, I need to install the 3rd and 4th together, & not one at a time. Any thoughts?

StaticFX
Jan 2, 2009, 09:38 AM
If I'm getting this right... the bios (F2 - setup) is showing all 4 gb. But in windows... u only see 3.

Well.. my guess is you are using xp (or vista 32). Max is 3 gb. Ram - you have to go to Vista64 or (xp 64 - not positive that XP64 can.. but iknow vista64 can)

ITstudent2006
Jan 2, 2009, 09:48 AM
Phaedrus:


You said the computer is listed as being able o handle 4 gb of RAM. Is this the computer itself or the Operating System, like StaticFX said there are limitations on OS' and the amount of RAM it can handle even if your motherboard supports 4GB 32-bit Vista x86only supports 3GB as does XP 32-bit. 64-bit OS allow for larger support so it depends on your OS.

I believe this is true if I am wrong please let me know! Hope this helps

phaedrus69
Jan 2, 2009, 10:22 AM
Very fast reply! Wow! Tried to reinstall one at a time -same result. Yeah, I'm running xp on this, so spent the extra $20 for another gig for nothing. Question is now, should I just leave the module in the computer, or will it make any difference? Oh, also, should I now reduce the amount of virtual memory, or leave it the same? Thanks so much! Saved me an expensive call to tech support. Would have been nice to know this before I ordered the RAM.

ITstudent2006
Jan 2, 2009, 10:27 AM
Very fast reply! wow! Tried to reinstall one at a time -same result. Yeah, I'm running xp on this, so spent the extra $20 for another gig for nothing. Question is now, should I just leave the module in the computer, or will it make any difference? Oh, also, should I now reduce the amount of virtual memory, or leave it the same? Thanks so much! Saved me an expensive call to tech support. Would have been nice to know this before I ordered the RAM.

I would take the module out, no need to be in motherboard if it's not capable of being used. And YES I would decrease the amount of virtual memory. Virtual memory simulates the hard disk as memory when RAM is low. Since you will be running at max RAM ths is probably not needed and can be lowered. Since you're running a 32-bit Xp OS and I'm assuming you're not going to hange anytime soon I would try and sell the mod. You have no use for it and it does no good sitting in a drawer!

Hope This Helps!

Curlyben
Jan 2, 2009, 10:50 AM
Just to clarify something here.
32 bit Operating Systems (Windows XP & Vista) allow for a MAXIMUM TOTAL memory of 4GB.
OS's that are specifically 64 bit have a limit of 16 exabytes of RAM, or approximately 17.2 billion GB!!
That includes any memory on your graphics cards as well.

I run 4GB RAM with a 512 MB video card, so windows only shows 3.5 GB of RAM.

So 3.5GB + 0.5 (512MB video) = 4GB Max.

ITstudent2006
Jan 2, 2009, 11:46 AM
Curlyben you're absolutely right I was trying to explain that you will not be able to use all 4GB with the x86 version. This is a limitation of 32-bit processing. There is only 4GB of addressing space and some of this is used by the system.(like you explained) How much depends on thehardware, but it is the remainder that can be used by memory addressing. So,the max you can address is 4GB minus however much your system requires. This
figure could be 3.2GB, or only 2.9GB, or some other figure entirely.

All 32bit operating systems can see a maximum of 4GB. It is a mathematical limit, not the OS. Vista x86 like XP x86 will show a little over 3GB on System Properties. This is normal. The "missing" ram is not really missing. It is used by the system and not presented to the user. There is a range of addresses at the upper end of 4GB that is reserved. In a system with less than 4GB these are logical addresses and are handled by the system
that way. However, when the system has 4GB it must block out physical ramto protect the reserved addresses. In addition, the BIOS will reserve some
additional address space for use by devices detected by the BIOS. (this info via Compt TIa A+ Study book)

Hope this makes sense!