Dell Dimension 8300 RAM upgrade question

[nsafreak]

Ok folks I thought I was going to get my system running with a higher memory speed again but it seems it will be a little longer before that happens. Like an idiot a few months ago I had bought a single stick of PC-3200 Geil RAM with a CAS latency of 2.5. Well I finally got around to getting another stick of RAM (Patriot) with the same CAS latency of 2.5 running at PC-3200 and the same capacity. I put the two matching sticks in the slots indicated by the manual but if anything the system seemed to run slower and the BIOS showed the memory speed still at 333Mhz. Now I found out that the pair of PC-3200 256MB sticks that came with the system are running at a CAS of 3.0. I had originally thought that if the CAS latency for the two new sticks was faster than the old sticks they would slow down to match but still work at the 400 Mhz bus speed. Apparently this is not the case. Does anybody know if I need to have all RAM running at a latency of 3.0 to get the memory running at 400 Mhz on this system? Or can I do a faster CAS latency of 2.5 for all sticks and get a faster system overall?

 

[FlyingPenguin]

Dell systems (actually most modern systems) are VERY fussy about memory. Modern mobos usually run in dual channel mode and dual channel is very sensitive to timing.

On a home-built system you can tweak the memory timing in BIOS but you can't do that with an OEM system.

I would strongly recommend you go to Crucial or Corsair's website and use their online database to lookup the EXACT memory that's GUARANTEED to work on that computer. Sell the other sticks you've got.

If you use two sticks (which you should in order to make use of dual channel memory) they need to be MATCHED sticks. Two sticks from different manufacturers with the same CAS timing are NOT matched sticks.

I am not sure what you mean by the bus speed. If this system was running at 333 Mhz memory bus speed from the factory, you CAN'T run it at 400Mhz just by installing faster RAM. The clock speed is set in BIOS - and it's not changeable on an OEM system.

OEM systems do not have timing settings so you can't manually change the CAS settings in BIOS. USUALLY BIOS auto-detects the CAS setting of them memory and sets it accordingly, but many OEM manufacturer's LOCK the CAS setting.

You shouldn't mix memory with different CAS settings. The system will be hobbled at the timing of your slowest memory.

 

[cobo]

There are many threads about this at the Dell Forums. The longest thread here.

I read most of them before I recently purchased some PC3200 for my Dim4550 because I had the idea I might want to upgrade to an 8300 board at some point.

Assuming you have a processor with an 800 FSB. If you mix CL3 and CL2.5 PC3200 in the 8300 it will be run at 333MHz. If you install either all CL2.5 or all CL3 rated sticks it will be run at 400MHz. This was true for most brands people reported trying.

CL2 might not boot at all, be run at a slower speed (266MHz or 333MHz), and in just one case it was reported to run at 400MHz.

CL2.5 will be run at CL2.5 but it doesn't make many noticable difference.

Also unmatched sticks may not run in dual channel mode, but I don't remember if the Dell 8300 board is picky about that - you can find more info about that in the Dell forum threads. PAT is only enabled on the 8300 when the first two slots are filled - it's disabled if all four slots are filled.

Try your CL3 and CL2.5 sticks installed seperately. See what CPU-Z shows on the memory tab to find out what CL they're run at and whether dual channel and performance mode(PAT) are enabled with each pair.
You could run some benchmarks like SiSoft Sandra, but I think you should try out the things you want to use your PC for with each pair to see if there's any practical difference.

 

[islandtechengineers]

Originally posted by: FlyingPenguin
Dell systems (actually most modern systems) are VERY fussy about memory. Modern mobos usually run in dual channel mode and dual channel is very sensitive to timing.

On a home-built system you can tweak the memory timing in BIOS but you can't do that with an OEM system.

I would strongly recommend you go to Crucial or Corsair's website and use their online database to lookup the EXACT memory that's GUARANTEED to work on that computer. Sell the other sticks you've got.

If you use two sticks (which you should in order to make use of dual channel memory) they need to be MATCHED sticks. Two sticks from different manufacturers with the same CAS timing are NOT matched sticks.

I am not sure what you mean by the bus speed. If this system was running at 333 Mhz memory bus speed from the factory, you CAN'T run it at 400Mhz just by installing faster RAM. The clock speed is set in BIOS - and it's not changeable on an OEM system.

OEM systems do not have timing settings so you can't manually change the CAS settings in BIOS. USUALLY BIOS auto-detects the CAS setting of them memory and sets it accordingly, but many OEM manufacturer's LOCK the CAS setting.

You shouldn't mix memory with different CAS settings. The system will be hobbled at the timing of your slowest memory.

they're also fussy about overclocking!!!

if there's a must to purchase more ram (again), head over to dell knowledge base and search on your mobo, they'll have a list of compatable rams for your system (should).

 

[nsafreak]

Thanks for all the help guys. Looks like I'll be putting the sticks I have up for trade and see if anybody wants to trade them for a matched pair of Crucial/Micron sticks of the same capacity but CAS 3 timing.