Tweaking Optimizing Windows.pdf - GEGeek

Advanced Settings tab of the associated IDE channel's properties page. For easy reference, here's a table of the different DMA
transfer rates and their corresponding maximum throughputs.
DMA Transfer Mode
DMA Mode 0
DMA Mode 1
DMA Mode 2
UltraDMA 33
UltraDMA 66
UltraDMA 100
UltraDMA 133
Maximum Throughput
4.16 MB/s
13.3 MB/s
16.6 MB/s
33.3 MB/s
66.7 MB/s
100.0 MB/s
133.3 MB/s
Swap floppy drive
This feature used to logically swap the mapping of drives A: and B:. Therefore, it is only useful if you have two floppy drives.
Normally, the sequence by which you connect the floppy drives to the cable determines which drive is drive A: and which is drive
B:. If you attach the floppy drives wrongly and obtain a drive mapping that isn't to your satisfaction, there normally wasn't any way
to correct this except to physically swap the floppy cable connections. However, with this feature, you can swap the logical
arrangement of the floppy drives without opening up the case. When it is enabled, the floppy drive that originally was mapped to
drive A: would be remapped to drive B: and the reverse goes for the drive that was originally set as drive B:.
Although this appears to be merely a feature of convenience, it can be quite important if you are using two floppy drives of different
form factors (3.5" and 5.25") and you need to boot from the second drive. Because the BIOS can only boot from drive A:, you will
have to physically swap the drive connections or use this feature to do it logically. If your floppy drive mapping is correct or if you
only have a single floppy drive, there's no need to enable this feature. Leave it at the default setting of disabled.
UltraDMA 100 IDE controller
This feature is only found on certain motherboards that come with an extra IDE controller. It allows you to enable or disable the
function of that controller. Please note that the IDE controller covered by this BIOS feature is different from the chipset's built-in
IDE controller. This extra UltraDMA/100 IDE controller is often added to provide UltraDMA/100 support in motherboards whose
chipset does not offer UltraDMA/100 support. Even if the chipset's built-in IDE controller supports UltraDMA/100, it is not controlled
by this BIOS feature. This feature is only used for the extra IDE controller.
For the purpose of avoiding confusion, I shall hence refer to the built-in IDE controller as an internal IDE controller while add-on IDE
controller will be known as an external IDE controller. If you want to attach one or more IDE devices to the external UltraDMA/100
controller, you should enable this feature. You should only disable it for the following reasons :-
- if you don't have any IDE device attached to the external UltraDMA/100 controller
- for troubleshooting purposes
- disabling the external IDE controller will free up two IRQs and speed up system booting.
This is because the IDE controller's BIOS doesn't have to be loaded and the external controller's often long boot-up check and
initialization sequence will be skipped. So, if you don't use the external IDE controller, it is recommended that you disable it.
UltraDMA 66 IDE controller
This feature is only found on certain motherboards that come with an extra IDE controller. It allows you to enable or disable the
function of that controller. Please note that the IDE controller covered by this BIOS feature is different from the chipset's built-in
IDE controller. This extra UltraDMA/66 IDE controller is often added to provide UltraDMA/66 support in motherboards whose chipset
does not offer UltraDMA/66 support. Even if the chipset's built-in IDE controller supports UltraDMA/66, it is not controlled by this
BIOS feature. This feature is only used for the extra IDE controller.
For the purpose of avoiding confusion, I shall hence refer to the built-in IDE controller as an internal IDE controller while add-on IDE
controller will be known as an external IDE controller. If you want to attach one or more IDE devices to the external UltraDMA/66
controller, you should enable this feature. You should only disable it for the following reasons :-
if you don't have any IDE device attached to the external UltraDMA/66 controller for troubleshooting purposes
Disabling the external IDE controller will free up two IRQs and speed up system booting. This is because the IDE controller's
BIOS doesn't have to be loaded and the external controller's often long boot-up check and initialization sequence will be skipped.
So, if you don't use the external IDE controller, it is recommended that you disable it.
SYSTEM BUS
16 bit recovery time
The PCI bus runs at a much higher clock speed than the ISA bus. So, for ISA cards to work properly with I/O cycles from the PCI
bus, additional bus clock cycles must be inserted between each consecutive PCI-originated I/O cycles to the ISA bus. By default,
the bus recovery mechanism inserts 3.5 clock cycles between each consecutive 16-bit I/O cycle to the ISA bus. This feature enables
you to insert even more clock cycles between each consecutive 16-bit I/O cycle to the ISA bus. For example, if you choose 3 cycles,
the bus recovery mechanism inserts a total of 3.5 cycles + 3 cycles = 6.5 cycles between each consecutive 16-bit I/O cycle.
Choosing NA sets the number of delay cycles to the minimum 3.5 clock cycles.
Most 16-bit ISA cards will work fine with the minimum 3.5 delay cycles. However, some ISA cards may require additional delay
cycles. Keep increasing the number of additional delay cycles until the card works properly. You might also need to increase the
number of delay cycles if you are overclocking the PCI bus. But if possible, set the 16-bit I/O Recovery Time to NA for optimal ISA
bus performance. Increase the I/O Recovery Time only if you are having problems with your 16-bit ISA cards. Note that this
feature is only valid if you are using 16-bit ISA cards. It has no effect if there are no 16-bit ISA devices in the system.
8 bit recovery time
The PCI bus runs at a much higher clock speed than the ISA bus. So, for ISA cards to work properly with I/O cycles from the PCI
bus, additional bus clock cycles must be inserted between each consecutive PCI-originated I/O cycles to the ISA bus. By default,