2 Fast 2 Furious

In order to maintain proper timing in a game, PC developers use a software timer. This can be done by determining the time required to complete a number of fixed calculations, by synchronizing game time with system time, or by relying on the fixed and accurate timer of the sound card. This prevents games from running “too fast.” If you were to run Quake on x86 compatible CPUs a decade from now, the game should play perfectly. Many games programmed for the PC-XT will run too fast on today's systems. Games programmed with this consideration for future compatibility should run superbly on the DreamX-1480. For these games, adding a faster CPU to the Xbox has the predicted results as adding a faster CPU to a PC. Games run as you expect, but in cases where the CPU was a limiting factor toward the ideal framerate, the performance is improved.

On a console, however, developers do not have to worry about different CPU speeds. The Xbox was always supposed to run with a fixed 733Mhz CPU. Therefore, games that do not take into consideration the future will be problematic for the DreamX-1480. When running at 1.48GHz, these games run at twice the speed that they should. The analogy is if you were forced to play Quake as if it were running in “timedemo 1” mode.

On a slower CPU it's OK, but it'll be too fast to play if your hardware is "too powerful." This speed may in fact be advantageous to a turn-based strategy game that’s too slow to be begin with, but input and navigation would also be twice as fast.

To correct this, the DreamX-1480 has a switch on the front panel allowing you to drop the speed to a normal 740 MHz. This switch can be used “on the fly” without having to turn off your Xbox or restart a game.

As the CPU is multiplier locked, the DreamX's turbo switch works by issuing the STP-CLK command to the CPU to force the CPU to run idle every other command. Ideally, any game expecting 733MHz should run appropriately at 740MHz. However, this isn't always the case. Even when adding this forced delay, the Tualatin has 256KB L2 cache CPU rather than the 128KB L2. AMD fans know that the difference between the Athlon64 3000+ and 3200+ is just 512KB versus 1MB of L2 cache. The difference between 128KB and 256KB is even more significant of an upgrade – 128KB is simply too small.

MPEG-2 Errors

A second issue with the 1.48 GHz CPU is that DVD MPEG-2 playback on the Xbox is also dependent on the 733 MHz clock speed for playback. Under 1.48GHz conditions, most, but not all in-game movies will pause every 3-5 second seconds, and then run again. The turbo switch makes no difference. Note that even games that run appropriately at the faster speeds will have trouble playing movies in MPEG-2. For DVDs, there can be significant lip-sync errors in which the audio and video is separated by seconds. For DVD movies, Friendtech's workaround is to use 3rd party software XBMP which allows you to specify your own video/audio sync delays. This brings us to the next point of the DreamX, the Media Key “modchip.”