Sound cards are usually the most problematic when they share IRQ numbers. They will be more susceptible to IRQ related mayhem when they share numbers with 1. TV cards 2. Graphics cards 3. SCSI or additional IDE controllers 4. Internal modems or ISDN. There are a few ways to remedy IRQ sharing on a PC. The first, and less complicated of which is to physically shift the installed PCI devices.

When SCSI, sound, and other PCI cards are first installed, Windows scans the PCI buss and assigns IRQ numbers automatically. By physically moving the cards, and rebooting, Windows will re-assign IRQ numbers. This procedure may take a few tries to achieve the desired number allocation, but it is by far the least technical solution to basic IRQ conflicts.

Although some devices can live harmoniously sharing IRQs, it is best to try and avoid it.

Don’t Use PCI slot #1 for your audio card.
An AGP graphics slot will often share the same IRQ with the PCI slot next to it on the motherboard, as will the ISA slot. The rule of thumb here is to not put any high throughput cards (SCSI or audio cards) in the first or last PCI slot.

Vcache

Go to your C drive, open the Windows folder, find SYSTEM.INI and double click on it. Scroll down the listed information until you get to “MaxFileCacheSize” and “MinFileCacheSize”. The amount of Vcache is usually set higher than most audio applications need, and an exceptionally high amount of Vcache will actually slow your application down. Change this setting to 16,000 for both the minimum and maximum values.

Window’s Cluster Sizes
When you perform a standard FAT 32 partitioning of a drive, it will set up the directory with 4K clusters. Using a program like Partition Magic will allow you to re-build the cluster sizes into larger 32K chunks without losing data already on the drive. What this means in basic terms is, Windows will process information from the drive in larger portions. This translates into an increased amount of data that can be written to/from the drive with less effort from your system. Compare this adjustment to filling and emptying a 3 gallon bucket 1 ounce at a time instead of 12 ounces at a time.

Use a permanent Swap File.
A Swap File, or “Virtual Memory” was created as a way to extend the limits of the installed RAM. When a system’s available memory is used up, Windows implements a system of buffering the oldest commands to a section of the hard drive, effectively allowing them to temporarily be “housed” until they are accessed again. The process of juggling the commands from virtual memory to active memory is where the Swap File got its name.

Windows automatically allocates the amount of hard drive space dedicated to Virtual Memory. It creates what is referred to as a “Dynamic Swap File”, meaning that no dedicated space on the drive is allocated for the Swap. The benefit of this is that you will have more drive space available for storage overall, but the bits of information that get put into the swap file can quickly become scattered all over the drive. Since Windows is putting this data wherever there is available space…it is actually increasing the amount of effort and time it takes to retrieve this data.

The alternative is to set up a “Permanent Swap File”. This involves determining a set amount of hard drive space in a specific location on the drive, and putting the overflow data there. Although you might not actually use all of the dedicated space for Swap functions, the drive will only have access a smaller, specific region of the drive…increasing the overall performance of the drive, and subsequent Swap File function.

The first step is to clear out the current Windows Virtual Memory settings. To access your Swap File, go to:

Start/Settings/Control Panel/System/Performance/Virtual Memory

Check “Let me specify my own virtual memory settings”. At this point, click “Disable Virtual Memory”, next click “Ok”. At this point windows will give you a warning message, click “Yes” (This warning is there for those who accidentally change settings without knowing what they are doing). Select “close” to exit System Properties. At this point you will need to reboot your system.

Before new Swap files can be recognized and implemented, your drive must be de-fragmented:

Start/Programs/Accessories/System Tools/Disk Defragmenter