My total ram installed is 4GB and ram usable is 2.43GB and I use windows 7 ultimate 32-bit. How can I increase it to at least 3.5GB?
Windows automatically does all in it's power to maximize the memory usage.
The only thing you can do is increase the memory available for user applications from the default 2GB to the maximum usable RAM (via 3GB switch or USERVA setting). However, there are two catches:
1. the application actually has to be programmed to make use of memory over 2GB on a 32bit operating system
2. you are taking away memory for kernel operations
Since your usable RAM is already down to 2.43GB any tweak in this are won't have much effect ~ might even make things worse.
I would recommend these instructions if you are familiar with command prompt:
try to update BIOS?
RAM chips was
failing do a MemTest
limitation of your hardware? not supporting more than 3GB
Depending on your video card and several other devices which may reserve chunks of memory, your total usable RAM when running a 32-bit version of Windows can be anywhere from I believe 2.25 to 3.8GB.
Pushing the Limits of Windows: Physical Memory
The 4GB limit for 32-bit Windows operating systems is TOTAL RAM, not just what is installed on the motherboard. In your case, I would guess that you have a video adapter installed with 1GB of video RAM on it. This video memory (as well as memory for other installed hardware) is mapped from the top down starting at the 4GB mark effectively overlaying any system RAM installed at those locations, hence the missing 1.5GB or so. To get around this, you can install a video card that uses much less video RAM. This will have an impact on graphics performance, especially if you are gaming with this system.
There is also a hack available on the net (you'll have to search for it yourself) to get around this limitation. The hack is not supported by Microsoft and it probably violates the license agreement. It may affect system stability and it has been known to cause some systems to fail to boot. The sources for it may also be questionable and you may be getting far more than you wish with this as well. It is unsafe on so many levels that I cannot recommend this course of action but want you to be aware of it if you choose that (potentially perilous) route.
You can't easily. 32 bit OS's have a 4 GB memory limit. The reason you see less than 4 GB usable is because of OS system usage and graphics card usage. I'd recommend installing win 7 64-bit and upgrading your ram to 6 or 8 gigs.
Upgrading past 4 gigs isn't going to make your computer faster per se, it'll just allow you to have more applications open at one time. More RAM is useful if you have a lot of tabs open or do video editing or other RAM intensive tasks. The reason you'll see a slow down is if all your RAM is being used and the OS is forced to use swap space (basically using the hard drive as RAM which is much slower).