Available Physical Memory Lower Than Total

Than

Available Physical Memory Lower Than Total System

Build a PC Total physical memory much lower than it should be. But i think when looking at Total Physical Memory one sees memory available AFTER a video adapter takes a chunk but before the. Ok first of all data storage capacity is always lower than the amount shown as there are overheads in the formatting of the storage device. Your hard drive may be 120GB but the amount available is 106GB so 14GB has vanished, this is because the file system always reduces this amount, also of the 106GB the operating system takes it chunk so you may be left with 90GB of space. Real and Physical. Physical memory is the amount of DRAM which is currently used. Real memory shows how much your applications are using system DRAM memory. It is roughly lower than physical memory. Linux system caches some of disk data. This caching is the difference between physical and real memory.

Physical
I've got a 5 yr old compaq that lately has been running really sluggish. I run regular virus/spyware checks using AVG and of course it's also doing real-time scanning. There aren't any processes running that I'm not expecting and none of them are hogging all that much memory. I noticed that my total physical memory is around 391 MB and it should be 512. I don't really know the expected difference between what the manufacturer states and what is given but I would guess it's less than 100 MB. I'm running Windows XP SP3. Are there any known problems that might be causing a sluggish computer or are my instincts correct in that I have a problem with my physical memory? I would also appreciate any other suggestions you might have for such a sluggish computer.
Available physical memory less than total

Total Physical Memory Available

Memory

Dear Sir, I have installed OS Windows 7 64 bit. In my system information, I am getting much lower physical memory than total physical memory. Total physical memory 5.92 GB Available Physical memory 1.92 Does this mean that in the current situation, my system is only capable of using up to 1.92 GB. Installed Physical Memory (RAM): 8.0 GB. Total Physical Memory: 7.94 GB. Available Physical Memory: 4.84 GB If I run stick #2 only in DIMMA2, I see: Installed Physical Memory (RAM): 8.0 GB. Total Physical Memory: 7.94 GB. Available Physical Memory: 5.31 GB So it looks like neither stick is dead.