A strange problem, indeed... I don't think it is DOSBox related, though. I've played the game for hours, and didn't notice any slowdowns.

Your problem could be caused by a _lot_ of stuff. Here's some of the things you could try:

- Check you CPU/GPU temperature after playing a game (any game, preferrably some graphics-intensive FPS or something like that). If the temperatures are very high, check the fans in your computer (they gather dust after some time, and have to be cleaned). DOSBox is very CPU intensive, so it might stress your CPU more than other software you're using
- Stop _all_ other programs when running DOSBox. This includes virus scanners, firewalls, and anything you might see in the tray area
- Install XP SP2 (why are you still running SP1?!) and all post-SP2-updates
- Install the latest drivers for your graphics card

DOSBox-related things you could try:

- Try ykhwong's build. On my machine, it's much faster than the standard DOSBox build, especially with SVGA games (only the "Collector's Edition" of TIE Fighter supports SVGA, AFAIK)
- Try different output methods (edit dosbox.conf)

Well I can immediately say that it's very likely not temperature-related. I just exited TIE Fighter after its latest slowdown, checked this thread, saw your reply, checked my video card tempurature, and it all was way in the green. I don't know how to check the CPU temperature itself.

And I refuse to install SP2. Everytime (everytime, no exaggeration!) I've installed SP2, my PC has gone schitzoid on me, randomly crashing and freezing and causing Windows itself to run slower. This occurs no matter how updated my motherboard and video card drivers are, and I don't use firewalls or virus protection software.

I'm thinking it's probably a program with programs open in the background. I've got quite a few of them. But then why would it be fine for a little while and then start to hiccup?

And what makes ykhwong's build different? I went to his site, and I don't see a link that's clearly labeled, "ykhwong's build". I only see a download for DOSBox 0.70 CVS.

SP2 won't do anything bad to your computer. If you have this kind of effects, then something's wrong with your system. I have installed SP2 on a lot of different systems, and never had troubles. It's being used in companies all over the globe. If there would be serious issues with SP2, we'd know it by now. Maybe it's time to reinstall your machine.

ykhwong's build has many features/patches the "standard" version doesn't have. Download the file on his site, and check the readme for details.

All i can say is that the game runs perfectly on my system, which is quite similar to yours (P4/2.3Ghz/Radeon 9600 Pro). The problem is your system or setup, not DOSBox.

I reformat my HD and reinstall Windows once every three months, BTW, so regarding SP2, no, I don't think it's a "I just need to reinstall Windows" issue. That pack is evil.

I tried out ykhwong's CVS build and it didn't run any faster. I also tried utterly destroying every program in the background, too, with a selective startup. That didn't help either. I also tried using other rendering solutions, which seemed to help at first, but eventually the problem still reared its head. Granted, I gained another precious few minutes, but...

One of the things I've noticed is that it takes a lot longer for the slowdown effects to start affecting in-flight gameplay. They start snow-balling almost immediately between missions and during briefings, though, and by the time I'm ready to head out into the mission the game is struggling. But once the mission starts? Smooth sailing... for about 30 minutes, anyway.

Even stranger, I've found that I can actually speed up the rate at which the game slows down by sitting in the concourse and running my mouse over the doors, one by one. It seems that opening and closing them is something my PC doesn't like to do and complains by slowing things down.

EDIT: Updating my drivers didn't help either. In fact, that seemed to slow down my PC as well. Damn.

The problem is your system or setup, not DOSBox.

This sounds like some app running in background, thinkink that your system is idle at the moment. Most likely - antivirus software, disk defragmenter, windows internal drive indexing, a shared computing or something. It may also be some memory managemnt app, asking windows to dump active memory to swap file. It's definitely a windows issue.

I wish I could figure out how to kill absolutely everything in the background except what I need to have sound, video, and a mouse and flightstick. Unfortunately, I have no idea which Microsoft "services" are necessary and which ones aren't. Lord knows if I do a safe-boot nothing related to games comes close to functioning.

I'd also like to be able to play TIE Fighter without having to reboot my PC.

Erm i understood it as you have to exit dosbox and restart it so you can
continue playing, but it's like you have to restart your system in order to
get things straight? Really odd.
Start the task manager and have a look at the memory/VM comsumption
(especially of the dosbox process) and if it's drastically more when it's
unplayable after some time.

Setting DOSBox to "Highest" priority seems to make a huge difference. I'm going to experiment with this some more.

Turns out setting "Highest" priority didn't make as large a difference as I thought. I get another few minutes, but then things start to slow down again.

As i already wrote, i'm pretty sure the problem is your setup, or your system. I guess you'll have to identify the source of the problem, but that can be a tedious proccess. It might be easier to reinstall windows, install _only_ graphics card drivers, and then try to run the game. You could create an hd image of your current install, which would allow you to switch back to your old windows install after the test with the new one.

Here's some more questions/things you could try:

You wrote something about a flightstick. What kind of stick is that, and do you have any special drivers installed for it?

Play a CPU- and graphics-intensive FPS game, like Quake 3, Doom 3, Half-Life 2, FEAR or something similar. I mean a game that will put stress on your CPU and graphics card. See if you have slowdowns with a game like this.

Uninstall all unnecessary drivers, like special mouse drivers

Unplug all USB hardware you do not need for playing

Try to play with sound disabled (in the game's sound setup)

Try to run DOSBox under Linux (should be possible without installing, by using a Live-CD like DSL or Knoppix)

Something additional to try: set "core=dynamic" and "cycles=max 50%" in your dosbox.conf
and see how long it lasts.

What does that do? Isn't max-50% equal to 10000 cycles?

EDIT: Well, whatever it does, it appears to have done something. I played for my usual 20 minutes and encountered no slowdown. However, I need to try a few more times before I'm willing to accept this as a cure.

Again, what exactly doesn "max 50%" do?

From what I know, if Dosbox is set to Max it will push for the maximum amount of speed possible - if you set it to max 50% it would only use 50% of your CPU but for a game like TIE Fighter that would be more than enough still.

Here's the dilly, though: I've tried running TIE Fighter under Dynamic/Max, and it runs like crap. However, when I run it under Dynamic/30000, it runs perflectly for 15-20 minutes before starting to show signs of slowdown (as what started this thread).

In my experience, DOSBox's "Max" setting ups it to 20000 or whereabouts. That's my guess, anyway, as I routinely get games to run faster by not using the Max setting. (And everytime I use the Auto setting, it just uses 3000 or Max and never anything in between...)

But, I suppose I shouldn't complain... DOSBox is a miracle in-and-of-itself. I just need to figure out how to pump the absolute most speed out of it for games like the X-Wing series and Wing Commander III and IV.

maybe try the limit option

(cycles max limit 30000 or so)

As Qbix said there are more options to try. Yet there is still something
wrong with your system that becomes visible when it is pretty much stressed.
As Addict and others already wrote, the most likely thing are overheating
(this can be various components) or background programs. But well, no idea...

Sounds a lot like overheating. With the P4's overtemperature throttling, users don't notice that their cooling is too low, because the CPU simply shuts off for a while or reduces speed if temperature gets too high. On most other CPUs, the system crashes, so you easily notice that something is wrong.

It also makes sense regarding the symptoms: Lower cycles = lower CPU stress -> longer play time. Other output options = lower CPU stress -> longer play time. Need to wait a bit until it works again -> CPU can cool off. Now some educated guesses: 3D flight mode might use many instructions that are emulated differently and let the CPU run cooler (= longer play time) while briefings might run some input handler in a tight loop that heats up just the wrong part of the CPU (= early slowdown).

Really, I'd bet it is insufficient cooling for your CPU, and you just didn't notice it up to now because of the CPU protection "feature" of the P4. Video card temperature doesn't matter for DOSBox. If this is a selfmade box, you may have installed the cooler incorrectly (too much heat-conductive paste, or none at all, or not thoroughly cleaned the cooler's ground plate and reapplied new conductive paste if you took it off) or have bad air flow inside the case. If it is an off-the-shelf box, it is probably dust buildup as was suggested earlier. In any case, take a look inside (after removing the power cord), vaccum the fans, coolers and rest of the case so that the majority of the dust is gone (no need to be squeaky clean), then close the case and try again. You may also want to check if the fans are still running correctly, since they tend to die over the years.
Heat problems are a common problem, because what was once sufficient gets continuously worse over time due to aging effects, then a few programs start to fail, and some while later, the system gets problems while idle.

BTW: You should reinstall your machine using SP2 and all security updates (start windows update again and again until no updates are left) and then install a virus scanner (like the free and well-known http://www.free-av.com).

Since you are missing the security updates of the past few years and have no virus scanner running, your system must be a biotope of malware by now. A decent virus scanner (i.e., not Norton) and the XP-built-in firewall (i.e., not ZoneAlarm), and if you're using IE or install a lot of software a regular spyware scan (Like the famous Spybot S&D at http://www.safer-networking.org) make your system faster by preventing viruses, spyware and other unwanted background processes invading your system. Those can slow down your system without being seen in the task manager, so you never know about them. A decent slim virus scanner doesn't slow down your system significantly, OTOH. You won't notice a difference while gaming.

I agree with Moe, it definitely sounds like an overheating problem.
Your cpu should certainly be capable of more than only 20000 cycles with "max" setting. I've just tried it on a notebook with a Celeron M cpu (single-core, 1,73 GHz) where DOSBox runs at ~66000 cycles at the DOS prompt, ~45000 in X-Wing's ingame menus and 59000-78000 in-flight (I'm using ykhwong's build, but usually there's no noticeable difference to the original release).
If DOSBox already starts up that slow, there's most likely something wrong with your cpu.