My computer has a dual-core 3GHz AMD processor and two GB of RAM. Our original intention was to build it with 4 GB RAM, but when we bought the components at the local computer store they only had the one memory stick in stock. (Yes, it would have been less expensive to order components on-line, but not a lot -- my computer builder is chief engineer at the radio station group where I worked, and he receives heavy discounts on parts.)

The computer works fine with "just" 2 GB RAM (I remember when I paid over $200 to upgrade my old 386 machine from two to four MB of RAM), at least, I think it works fine, but how would I know if it didn't?

I can purchase an identical RAM strip (its a T800UB2GC5) for $21.95 plus $10 shipping, ~$32 total.

Scary thought: $21.95 is about 1/10,000th of the cost per byte of my previous upgrade!

So, two questions. (1) Is $21.95 a reasonable price; and (2) what do I gain by having 4 GB instead of 2 GB of RAM?

FWIW, I don't do computing that is RAM intensive, at least I don't think I do. I don't do video editing, for instance. I play DOOM (Z-DOOM, now that my platform is 32-bit) once in a while, spend some time surfing the internet, do spreadsheets and word processing. I'm probably using less than 10% of the capability of my computer as it sits.

tanstaafl.

edit: Better price: $21.30 + $8.25 shipping = $29.55
edit2: Better price: $23.00 + $0.00 shipping + $1.90 tax = $24.90

Worst deal so far: $174.00 + $13.90 shipping.

Don't bother to update the RAM beyond 2GB. By the time you'll need to do it, you'll be looking at a new machine which will invariably require different modules.

If there's no negative impact from running a single module, then keep at it.

Newegg is always a good place to go to do research on computer parts, and you'd be hard-pressed to find a consistently better reseller, too.


Bring up the task manager (Start->Run->taskman; Ctrl-Alt-Del, T; Ctrl-Shift-Esc) and open the "Performance" tab. Verify that the Total Physical Memory looks right. Now watch the Total Commit Charge. If its value hovers near that of Total Physical Memory, you have too little memory for what you're doing. Note that the current value of the PF/Page File Usage graph is actually the same as Total Commit Charge. (Which means that it really isn't that related to the page file at all.) Regardless, you can use the Page File Usage History graph to see what your memory usage looks like over time, so you don't have to constantly watch that number change.

There usually is a slight performance penalty for not having the same size and type of memory on both channels. The penalty is so small however that you're not going to ever notice it unless you start running memory benchmarking utilities.

It would seem slow when you tabbed between applications, and every time it seemed slow the hard-disk light would be on.


I'm guessing that you intend this to mean "no longer 16", but in fact your platform being "not 64 yet" means you wouldn't see all the benefit of adding 2GB more: the memory usable by Windows would max out at about 3GB, the exact figure depending on what PCI/PCIe peripherals the machine has.

So much for RAM size; it's also conceivable that RAM bandwidth could be improved by adding a second memory module, as some motherboards these days have multiple memory buses and can interleave accesses if RAM is populated in matching pairs. However, all this would gain you if so is additional speed, and if your PC is already fast enough there's no need for an upgrade for bandwidth reasons either.

Peter

Indeed. I recently had a client with an old Dell who complained about speed problems. It was clear to me that after a few programs were open the hard disk was doing most of the work from the pagefile.

I wish the solution hadn't cost him, though. Sadly he bought his computer during those four minutes when RAMBUS was popular. He insisted on keeping the computer, and it ended up costing over $150 for something like 512MB of memory. Crazy.

I'm guessing that Total Commit Charge is the little skinny column on the left. It stays pretty much at just under half of the Total Physical Mmemory as I type this.



The most severe memory usage I have is when I am removing DRMs from audiobooks. The software plays the audio in real-time, transcoding to MP3 and removing the DRM. I can specify how many audio streams to run concurrently, and have found that the limit on my computer seems to be 20. More than that and I get file corruption. I think the bottleneck is CPU usage, not RAM usage, but strangely my CPU usage graph never goes over 65-70% while running the program. The RAM usage runs pretty constant at about 2/3 of the Y-axis on the graph when I am playing/transcoding 20 streams at once.

tanstaafl.

Dammit. They changed it under Vista again. I don't know what those numbers mean anymore.

Under Vista, the magic number's in the Task Manager status bar. Mine says "Physical Memory: 54%", which agrees with the "Memory" bar that Doug's looking at (1.07GB on a machine with 2GB). The actual amount of recognised memory is shown as "Physical Memory / Total". Don't worry about the fact that the "Free" number is really low (mine says zero) -- Vista is insanely aggressive about caching things.