Another system requirements related post.

I'm running a pretty old system, I suppose:

- Athlon XP 2400 (Thoroughbred), FSB 266MHz
- MSI K7T Turbo2 board, KT133A chipset, 133MHz (default) system clock (adjustable up to 150, but I haven't been able to achieve stability that high; decreasing the CPU multiplier from its default (15) just seems to prevent booting)
- 768MB PC133 SDRAM (512 + 256)
- 20 GB HD, probably spinning 5600 RPM (age-based estimate)
- 128 MB GeForce 4000MX (good budget card, no true hardware pixel/vertex shading)

I just upgraded the memory, actually -- bought another 512 MB. So I was at 256 MB. Cranking Doom 3 all the way down, it actually ran fine. The patch helped, too. Interestingly enough, 256 MB is below system requirements on the box. It says 384 MB MINIMUM, and yet I was able to play just fine.

Yet, my upgrade to 768 MB doesn't seem to have actually improved performance in Doom 3 much. Turning on any additional effects and such immediately drops me back to the performance I was getting from the "out of box" configuration.

I know that the speed of the system bus here is the most likely culprit for the lack of performance increase from adding memory, but it just seems that going from below minimum requirements for RAM to well above it should have done something.

Anybody care to share similar stories or provide some hardware discussion to explain precisely what's going on? I don't really need help; I know that I need to get a new system if I want the best that Doom 3 can offer. Just seeing if there's anything worth talking about here. If nothing else, people who are on the fence about upgrading their machine or starting from scratch with a new system in order to run newer high-end games can get from this that at least DDR RAM is necessary.

Ultraviolet said:

but it just seems that going from below minimum requirements for RAM to well above it should have done something.

When I upgraded from 512 to 1.5 gigs of ram, I didnt see any special increase in framereates but I did see an end to loading hangs. My hard drive sure as hell was spinning a lot less. This is for obvious reasons of course. No longer did it need to read from virtual memory as much. So I didnt get 3 second pauses every time I opened a door.

But on that same note, you can see that even 512 ram wasnt enough for really smooth gameplay, despite the rest of my specs (2.4 ghz P4, X800XT PE).

It has to be either that 5600RPM hard drive or your front-side bus. My guess is the FSB.

kc32 said:

It has to be either that 5600RPM hard drive or your front-side bus. My guess is the FSB.

As I was kinda getting at (may have forgotten to actually say anything at all), I think it's more the memory, specifically, than the FSB. The FSB is going to govern the speed at which the processor interfaces with the rest of the system, but the memory is the resource that that interface is going to be using the most. So uh, anyway, the memory running at the same speed on a DDR-enabled FSB would probably still yield the same results (if such a setup were even possible).

The thing about my post up top is that I kinda explained the solution to my own problem -- gotta buy a major upgrade. All I wanted out of this was discussion, really, and I guess some hardware-illiterates could glean that they will probably have to upgrade fully rather than just tweak up a bit to get decent performance.

With your FSB, the memory's not going to matter much. What I don't get is why there's such a slow bus attached to an Athlon XP.

The frontside bus for (non-64) Athlons is DDR, so it transfers data twice per clock cycle.

kc32 said:

With your FSB, the memory's not going to matter much. What I don't get is why there's such a slow bus attached to an Athlon XP.

Because I dumped a 266 FSB Athlon XP onto a 133 MHz system bus.

Bloodshedder said:

The frontside bus for (non-64) Athlons is DDR, so it transfers data twice per clock cycle.

Can it burst like that on a 133MHz bus? I wouldn't think my board would support that.

I'm running my computer with a 2.8+ barton and my FSB is only set to 166mhz. As a matter of fact, I can only set it to 200mhz as a max.

And you're actually running it with SDRam?
I didn't know they made mobos that supported SDR ram for the Socket A CPU's.

Before DDR matured and caught on, PC133 RAM was actually faster to use with Socket A chips, and was most used when the Thunderbird core was predominant (before the Athlon XP). The most popular chipset was VIA's KT133A.

Also kristus, you may be running at a 166MHz bus speed, but the bus speed figure most often advertised for Socket A processors is the "effective" speed caused by DDR, which in your case is 333MHz.

Socket A processors came in no less than 4 different bus speeds: 100MHz (200 DDR), 133 (266), 166 (333), and 200 (400).

Also

Faint said:
Can it burst like that on a 133MHz bus? I wouldn't think my board would support that.

I have no idea what you are asking.