Won't recognise new memory

lonestarfan

I have a dell dimension E521. Put new memory from (2x1gb matching pair) crucial in slots 1&3. Moved the old memory (2x512mb) to slots 2&4. Turned it on. Now it Says only got 512mb. Slower than watching paint dry. Says slot 1 2 & 4 is empty. Ive pushed in firmly. They r correct way round. Any ideas now as a pc running so slow is a recipe for RAGE!! Thnx anyone.

aerostar

Insert each memory stick in turn and see what the result is, it is quite possible that your board may only take a certain amount of memory and you have exceeded its specification.

Also put them in consecutive slots, do not intermix sizes as you said above.

Did you run the crucial memory scanner on their site, or have you just bought memory from somewhere else ?

fwor

Assuming it's the correct spec and you've confirmed that the dual-channel pairing works in the way you describe (i.e. 1&3, 2&4), what may be happening is that the BIOS is using the timing (via SPD) of one slot, assuming that all slots will have the same timing, testing the next slot and not passing initial test - hence only finding one slot.

Have you checked the CAS latency marked on both new and old to see if they are the same?

Try just the new memory in and see if it boots. Then try putting the old memory back in different slots.

Be aware though that if old and new are different spec, the slowest common denominator is likely to be used.

lonestarfan

Many thanks. I just rebooted & for some reason it's recognising it now! I did run the crucial scanner & also spoke to them to double check. Really found them v helpful - this forum recommended them to me.

macman

I had this problem recently and the issue was that the new RAM was high density and the old was 'normal' density. One or the other would work in either slot, but not together. Crucial ID'd the problem for me instantly and swapped it in 24 hours, the replacement worked fine.
It's for this reason that I always buy RAM from Crucial. Not the cheapest, but the support is first rate.

lonestarfan

macman wrote: »

I had this problem recently and the issue was that the new RAM was high density and the old was normal density. One or the other would work in either slot, but not together. Crucial ID'd the problem for me instantly and swapped it in 24 hours, the replacement worked fine.
It's for this reason that I always buy RAM from Crucial. Not the cheapest, but the support is first rate.

You helped me decide to use crucial when I posted back in Feb -thnx. The leaflet that came with the ram was helpful too about installation & I'm glad i did it myself as it saved me loads of money. Hope it encourages others to have a go.