![]() Your question is specific to DOOM but other DOS games are in a similar situation. on an 8088 with a VGA card), the hardware takes care of specifics - for example on an 8088 the bus unit will split up 16-bit accesses. On platforms where this can’t work in hardware ( e.g. So REP MOVSW or REP MOVSD with no waiting in software, once the program decides to write a frame, is perfectly fine, and will go faster and faster as the underlying hardware improves. Such shenanigans are impossible for other device types in PCI, which is why PCI sound cards have so much trouble providing compatibility with programs written for ISA sound cards.)Ī faster bus and/or faster video memory immediately leads to higher performance in video-intensive programs because software doesn’t need to be careful about how it accesses video memory (except on CGA, and on all platforms with vertical blank synchronisation if it cares about tearing). (This is the reason why there’s a specific “VGA compatible controller” device type in PCI. So accesses to the VGA registers and to the VGA buffer (at 0xA0000) go directly to the main PCI VGA compatible adapter in the system, with no change required in the operating system or programs running on it. PCI goes to great lengths to preserve backwards compatibility with ISA-based VGA, providing support for “VGA compatible” adapters so that they can appear in memory at the same locations and use the same I/O ports as ISA VGA cards. It runs faster with PCI graphics cards (and VLB, AGP, and PCI Express cards) than with ISA graphics cards because the supporting bus is faster, so reads from and writes to video memory take less time. Continued abuse of our services will cause your IP address to be blocked indefinitely.DOOM itself doesn’t do anything special to benefit from PCI graphics cards. Please fill out the CAPTCHA below and then click the button to indicate that you agree to these terms. If you wish to be unblocked, you must agree that you will take immediate steps to rectify this issue. If you do not understand what is causing this behavior, please contact us here. ![]() If you promise to stop (by clicking the Agree button below), we'll unblock your connection for now, but we will immediately re-block it if we detect additional bad behavior.
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