I installed new computer memory, but it isn't all being read.?

Put the two 512's in slots 1 and 2, boot up. Does it read 1024 now? No? Just shows 512? Put the two 512's in 1 and 3 slots. 1024? Don't know what mobo the Dell 4700 has,(motherboard),but it sounds like you have the mobo manual. Does it say like 'sticks' of ram should go in banks,(slots), 1 and 3, plus 2 and 4? Some mobo's manufacturer's use 1 and 2, 3 and 4. Some use1 and 3, 2 and 4. You may need to check the 512's first, then install the 256's. Check out Hardwaresecrets.com. Click on the Memory heading at the top, and peruse the sub-headings.

Firstly Update your Pc Bios (Firmware), the latest version is A10, which suggests that at least 9 bios updates have been made since the Pc's first Manufacture.

Bios Updates are worth doing because they add extra Features, and Bug Fixes and could well solve your problem, Iv'e posted the link for the 4700 (not 4700c) for you.

Download it and run it.

Another good way to test the memory is to install 1 Dimm at a time to see if they all work on their own, if they do then the reason why you can't see all the memory is either the PC can't support that much or the Bios is at fault.

Don't believe any rubbish about Shadowing, You will only loose a small amount of ram when this is happening not 200 meg!!

I had a similar problem. Try puting the two 512s in slots 1 and 2. And the two 256s in slots 3 and 4. Of course YMMV.

Now let��s cover a few reasons why your additional memory might not be recognized:

First, of course, the new memory modules may simply be defective. Although not terribly likely, this does happen.

Second, you could have the memory installed wrong. Remove it and reseat it, checking very carefully that you have it seated correctly. The notches in the memory module and socket are supposed to prevent incorrect insertion, but believe me, they don’t make it impossible,I have seen this done and also with one end not completely seated.

Third, you could have bought the wrong type of memory. Four types of memory have been used in Pentium 4 systems: SDRAM, RDRAM, DDR and DDR2 (SDRAM and RDRAM are not currently being used in new systems, but are still found in older Pentium 4 systems). Note that this is the TYPE of memory, each type is totally different and totally incompatible with the others because they work completely differently. Any given system will generally take one and only one memory type. Subtle differences in the connectors are supposed to prevent inserting the wrong type of module, but as I noted above, it’s still possible to do it. So, the first question you need to be certain of is “what type of memory do I need” and you must buy the correct type.

Fourth, even if you have the right type of memory (a module that would otherwise work in your system), when adding a module to an existing system that already has installed modules, you can run into compatibility issues between the modules. The modules have to be same,same type etc pc 3200 and the same speed etc 677mhz

try to look on bios setup, maybe it was disabled there, or check the voltage of your memory, check the label check if it is pc 2300, its better to bring along 1 of your 256 memory in store when buying, so that it will match the voltage...

Sounds like 264mb may be allocated for video usage.