bag's Flight Sim System

Here's a run-down on the system I'm currently using to run Microsoft Flight Simulator 5.1:

• CPU: Intel Pentium 75 currently overclocked at 90-MHz.
• Motherboard: Acer AP5C with Intel Triton chipset, 256 KB L2 cache.
• BIOS: The AP5C comes with an AMI BIOS. However, I have been switching back-and-forth with the Microid Research BIOS v3.27. As near as I can tell, there is no difference in performance or reliability between the two BIOSes. However, the Microid BIOS does boot up faster.
• RAM: 16-MB (expandable to 128 MB). Having recently upgraded from 8MB to 16MB, I can heartily recommend 16MB! With memory costing only $10 CDN per MB, this is a "no-brainer".
• Hard Drive: 420 MB Seagate ST-3491A (Medalist). With my current software load (FS 5.1 CD, BAO's Flight Shop, Microsoft's Japan Scenery, Gametek's British Isles scenery, several other shareware scenery packages and utilities, several encyclopedias, Star Trek Omnipedia and Technical Manual, not to mention office apps), I am in need of a hard drive upgrade. I think 2 GB is the next step up.
• Sound Card: Sound Blaster 16.
• CD-ROM Drive: Sony 33A double-speed.
• Joystick: Microsoft SideWinder 3D Pro. This is the latest and greatest input device from Microsoft. It sports a stick that moves left-right (ailerons), front-back (elevators) and twists (rudder). It's certainly an interesting and controversial little puppy and I will have much more to say about it later. In the meantime, I have switched over to...
• Flight Yoke: CH Products Virtual Pilot Pro. For civil aviation aircraft, a flight yoke is really the only way to go! The only problem was mounting it on my desk (or any desk for that matter). My desk has a depressed typewriter well where I have my keyboard located. The monitor is at the back of the desk. I built a slightly tilted wooden platform that sits in the typewriter well. The yoke attaches to the platform so it is positioned just above the keyboard and in front of the monitor. The yoke can be rotated without hitting the keyboard and both the yoke and keyboard are useable at the same time.
• Game Card: Interact's High Speed Game Card. This card is adjustable through software and I have it set to the fastest setting. I'm not saying this card works better than the game port on my Sound Blaster (I can't really tell), but being adjustable certainly can't hurt. Besides, it has two game ports, in anticipation of adding rudder pedals. Interact is a division of STD Entertainment (USA) Inc.
• Video Adapter: Diamond Stealth 3D 2000 (PCI, 2MB). This card is a SCREAMER and very affordable. My old ATI VGA Wonder (ISA) video adapter was clearly the weak link in the system and while I had planned to upgrade to either an ATI Mach 64, Matrox Millenium or Hercules Stingray, both Diamond and ATI released moderately-priced 3D cards at about the same time. My decision was heavily influenced by Bob White at PCM&E. My frame rate on Flight Simulator 5.1 is around 10 fps under the worst conditions with all options enabled, which is about 5 to 8 times faster than with the old ATI VGA Wonder card. Typically, the frame rate is around 15 fps.
• Monitor: Delta DM-142M. One of the better monitors in its day, this interlaced 14-inch SVGA multiscanning monitor certainly pales in comparison to even the cheapest of today's non-interlaced monitors. But, it still works OK and I have no short-term plans to upgrade it.
• Operating System: MS-DOS 6.22

Overclocking

Many people are having great success in speeding up their Pentium CPUs by increasing the system clock speed, a process known as overclocking. To overclock your CPU, you simply set the system clock on your motherboard as if the CPU was stamped with a higher clock rating. At the higher system clock speed, all CPU-related functions will run faster by a ratio equal to the change in system clock speed. For example, if you increase the system clock speed from 100 MHz to 120 MHz, CPU-related functions will run 20% faster. In my case, I was able to successfully increase my system clock from 75 MHz to 90 MHz for a 20% increase in CPU speed.

For flight sims, the goal and main benefit of overclocking the CPU is to increase the display frame rate by reducing the CPU time involved in generating each frame. Or, equivalently, to allow for more detail in each frame without sacrificing frame rate. Either way, you get a smoother, more realistic simulation as the speed of the CPU increases. Of course, the CPU isn't the only factor in determining the frame rate, but it is a significant one. The other significant factors include the speed of your video adapter (the faster, the better) and the amount of main RAM you have (the more, the better). However, overclocking your CPU is probably the cheapest and easiest way to improve frame-rate.

So, how do you do it? Consult your motherboard documentation to find out which jumpers are involved in setting the system clock speed, or selecting the type of CPU. If your motherboard supports CPU types and/or speeds faster than your current CPU, then you're in luck. Just follow these steps:

1. Save your work and powerdown your system.
2. Open up your case and carefully change the jumpers to the next higher CPU type and/or speed setting as described in your motherboard documentation.
3. Reassemble the system and start it up.
4. Run the system for a while to make sure that everything is working. Try a few benchmarks to confirm the speed increase.
5. If you're satisfied that everything is running OK, repeat the preceding steps for the next higher CPU type and/or speed.
6. If your system malfunctions in any way, back off to the previous slowers settings that worked.

In my case, the Acer AP5C motherboard supports 75 MHz, 90 MHz, 100 MHz, 120 Mhz and 133 MHz CPU types. The selection is made with Jumpers 9, 10 and 11 and the documentation is very clear on the settings. I tried 90 MHz, 100 MHz and 120 Mhz. At 100 Mhz and 120 MHz, my system didn't boot -- the CPU didn't execute a single instruction of the BIOS code! So, I backed off to 90 MHz, where everything has been working just fine for weeks. Your mileage may vary.

WARNING! As the clock rate increases, so does the heat generated within the CPU. Therefore, if you don't already have a CPU heatsink and fan installed, I strongly urge you to install one before you start experimenting with overclocking!