Well, I've got a very old system:1.6 GHz Pentium IVATI All-In-Wonder Radeon 7500 32MB (Didn't it say 64?)512 MB RAM DDR400ASRock P4VM800 motherboardAnyway, I'm thinking of upgrading it a LITTLE bit (my wallet is empty)... just for keeping it for about a year before I get a new one... and yes, I'm keeping with FS9 (altough there are so much lowest-end users like me that make FSX work decently). I'll change the ATI for an GeForce FX5500 256MB, and upgrade the RAM to 1 GB. I was thinking of leaving my comp with 1.5GB RAM, but I don't have enough money.Anyway, in the board's installation guide, it says that it has "2 DDR DIMM slots: DDR1 and DDR2" (just copied exactly from the guide):"1 DDR DIMM Slot Supports PC3200 (DDR400),Max 1GB2 DDR DIMM Slots Supports PC2700 (DDR333)/ PC2100 (DDR266), max 2 GB)"At DDR1 I have a generic 512MB DDR400, and it's working OK. I saw a couple of memories at Newegg, both at $44.99, but one is a PC3200 and the other is a PC2700, same brand. My fear is that if I buy the DDR400 and my DDR2 slot does not support it (as I suppose reading the manual, I'm willing to stand corrected), I will end up with an useless plastic/silicon piece.The question: which do you suggest me to buy? DDR400 or DDR333?Thanks in advanceLuis Miguel

Any idea?

I can't give you a direct answer but the following link might help.It's the Kingston Memory site configurator. It will ask you for various characteristics of your machine and give you a selection of appropriate memory.You don't have to buy Kingston's but just note the type of memory they suggest. Other memory manufacturers have similar configurators. Try a web search.[http://shop.kingston.com/default.asp?bannersource=comju]EditI just remembered that kingston also has several tutorials and guides under the heading 'Memory Tools' at kingston.com.

<<"1 DDR DIMM Slot Supports PC3200 (DDR400),Max 1GB2 DDR DIMM Slots Supports PC2700 (DDR333)/ PC2100 (DDR266), max 2 GB)">>What that means is that if you are only using 1 memory slot, you can run the memory at PC3200 (DDR400) speed and you can put a max of 1GB (ie a 1GB stick of memory) on the board. If you use both memory slots, then you can only run the memory at PC2700 (DDR333) or PC2100 (DDR266) speeds and you can put a max of 2GB (ie 2 1GB sticks) on the board. I believe faster memory will generally work at a slower speed (assuming the same memory technology (ie DDR or DDR2 etc), but not the other way around :->. Its possible that if you put 2 memory sticks in, while running at a slower clock rate, might enable dual channel or interleaved memory access with could actually increase the total memory throughput, but you would need to check the motherboard manual to see if it supports that.Timhttp://beatlesblog.spaces.live.com

I have to agree with Tim. I just went thru this with my PC and what I discovered is that my PC runs faster with LESS memory if it is configured for dual channel (DDR=Double Data Rate).I actually had 2.75 gigs of memory installed BUT at different speeds and configurations (ie 1 gig + 512K). So, when I took out the older slower memory (.75 gigs) and left it at 2 gigs of fast memory on dual channel my performance actually improved. I think Tim hit the nail on the head. Based on what I just discovered, I would recommend that you put 1 gig of the faster memory in the first slot and you will be pleased with the results.The other thing I discovered is that no matter how much memory you have or how fast it is, it won't matter if you have an older, slower video card.