RDRAM RIMM

Buyers will have to be careful when doing manual upgrades to their CPU/Mainboard/Memory with the i820 based mainboards, as the three models of RDRAM are compatible only with Intel CPUs that match their bus speeds.

Here's the chart again that visually describes the compatibility issue:

PCxxx Memory Bus Speed: Processor Host Bus 100 MHz: Processor Host Bus 133 MHz

PC600 300 MHz Supported Not Supported

PC700 356 MHz Not Supported Supported

PC800 400 MHz Supported Supported

From these details we can see that anyone using a 100MHz based Pentium III CPU will need to use either PC600 or PC800 RDRAM, while PC700 RDRAM will not be supported.

Likewise, 133MHz Pentium III owners will need either PC700 or PC800 RDRAM in their machines, as the PC600 RDRAM spec isn't supported in this case.

Remember that the VC820 mainboard, as well as the other i820 mainboards that will be hitting the market over the next month, all support each of the three types of RDRAM, it's the CPU that is the disqualifying factor.

In addition, multiple types of RDRAM within a mainboard's RIMM banks will default to the slowest RIMM's speed if the types vary. This means that if a user equips a PC with one PC800 RIMM and one PC600 RIMM, the board will assign both RIMMs to operate at the PC600's 300MHz bus speed.

Other features of the VC820 are less intriguing, including the inclusion of the well-received ATA-66 support for four IDE HD channels, as well as the removal of any ISA ports/legacy support on the board itself.

This isn't to say that the i820 doesn't support ISA ports, indeed you can bet that you'll be seeing i820 mainboards from other vendors that offer one or two ISA slots in certain models. The VC820 though is content to offer five PCI slots, one AGP 4X slot, and an AMR riser port for miniscule audio or modem cards.

Finally, Intel has included Creative Lab's Sound Blaster PCI 128 ES 1373 engine on the VC820 mainboard, which is probably the best integrated audio chip on the market currently. Offering support for 128 voice wavetable, as well as MS DirectSound3D, the ES 1373 is a good partner for any application your PC can run if your budget can't see fit for an aftermarket product.

We doubt that users who are purchasing the VC820, which again is a high-end desktop solution, will use the integrated audio for very long.

Instead they'll likely upgrade to an MX300 or SB Live! card for full audio capability, which we'd recommend for complete enjoyment of the latest entertainment apps.