I need bandwidth!
XP seems to be the suffix to use these days and that’s no surprise, considering that manufacturers want to associate their products with Microsoft’s Windows XP. Whatever the “XP” means to you, for manufacturers it means showing that they can keep up with the latest and greatest. Over the past year, Iwill has shown that it can do just that and more. Not only has it made a huge name for itself in the enthusiast community, Iwill also keeps tabs on the professional IT market, with boards that support the likes of dual Xeon processors and more.
There has been much talk about memory bandwidth with both the Athlon and the Pentium 4 (P4). Evidently, we all know that the best platform for the P4 to run on is a RDRAM-based solution. Because of its fast memory bus running at 400MHz (and soon 533MHz), the P4 obtains peak performance when paired with equally fast PC800 RDRAM. Unfortunately due to high prices, Intel was forced to introduce different solutions for its P4. On the other side of the river, AMD’s Athlon is also very much held back by memory bandwidth. Although not to the degree of the P4, the Athlon has a lot of growth potential. In fact, if the Athlon were using a quad-pumped FSB like the P4, it too would be significantly chained by current DDR RAM standards.
After being idle at PC2100 for a while, DDR RAM is moving forward as we see more and more modules on the market able to operate at 2400 and 2700. However, all this is being held back by the Athlon’s 266DDR (133MHz x 2) FSB ceiling. While it’s possible to run the Athlon with an FSB setting higher than 133MHz, stability issues come into play. Despite popular beliefs however, most overclocking stability comes from the peripherals on the motherboard. Cards and devices that use the PCI and AGP bus operate in co-ordinance with each bus’ specified speeds, which are ultimately governed by the FSB speed.
I hate fractions!
If you were a fan of the recent Iwill KK266 boards, you’ll immediately remember how strong it was on overclocking. Iwill hasn’t stopped since the success of its KK266 and in fact, has gone forward to produce some of the most overclockable boards in the industry. Iwill’s latest board, the XP333-R which we’re taking a look at today, is probably going to be one of the most, if not the most, overclockable boards ever.
Overclocking today is easily done and usually accomplished by adjusting the frequency of the FSB or Front Side Bus on the motherboard. However the FSB frequency directly governs both the PCI and AGP frequencies, and as a result both bus ports will operate out of spec if the FSB is set too high. So if Intel and AMD are planning to continually increase FSB speeds, how would they ensure that PCI and AGP cards will operate in at the proper frequencies? The secret lies in frequency dividers. For example, to keep the PCI bus running at its specified 33MHz speed, a processor using a 100MHz FSB has a 1/3 FSB divider. In the same manner, a 133MHz FSB system has a 1/4 FSB divider to keep PCI speeds clocked to specifications. The AGP port is also kept stable using the same method. To keep the AGP port operating at say 66MHz, a 100MHz FSB system would employ a 2/3 AGP divider.