I have an HP Compaq DX 2300 Mini Tower with an Intel Pentium Dual-Core E2160, 1.8 GHz processor, 4 GB of 667 MHz DDR2 RAM memory and PNY Geforce GT 240 (512MB GDDR5). I have just now changed over to 64-bit Windows 7 Pro from 32-bit version of Windows 7 hoping to get a good use out of 4 GB of RAM. Something seems odd, though. In BIOS, you can clearly see 4096 MB available, but in the 'System Properties' it says 4GB installed (2.75 GB usable).
What a disappointment. Or maybe not. When I look at my memory usage widget on my desktop, I can see computer using 25% of RAM immediately after boot-up which equals 1GB of RAM, which is about double of what 32-bit version uses (500-600 MB) right after boot-up. Could it be that all RAM is usable, but the 'System Properties' are wrong. I use this computer mostly for Adobe CS 5.5 Web Premium Suite applications and some video editing with Windows Live Movie Maker 2011. Adobe Premiere CS 5.5 requires 64-bit version of OS already although I don't use it. I am just mentioning this because maybe that's the sign of things to come. Dreamweaver CS 5.5, Photoshop CS 5.5, Illustrator CS 5.5 and Flash CS 5.5 are still OK with 32-bit OS.
4 GB is RAM limit on my machine. Should I go back to 32-bit version or am I still better with 64-bit version?
^ to do that he would need to go to 8 gigs of ram. He indicated His system limit is 4 gigs - So Not possible.
You have a feel for how the performance was under 32 bit Win 7. Try it for a while using the 64 Bit. Then go with which ever performs better in real life.
With 4 gigs ram, Myself I generally go with the 32 bit version and except the loss of about 1/2 gig. 64 bit has slight more bloat compared to the 32 Bit which tends to offset performance advantage. If 4 Gigs and planning on increaseing, then 64 bit is the only true choice.
Open your resource monitor and click on the physical memory tab. you should see a breakdown of in use / modified / standby and free memory. Is any alot of it "hardware reserved"? Some video cards reserve a portion of memory as hardware reserved. Also check your msconfig to turn off unneeded startup items that could help free up some RAM.