Intel's Pentium 4 with 533MHz Bus and The i850E Chipset
2.4 and 2.53GHz performance with a 533MHz Front Side Bus

By, Dave Altavilla
May 6, 2002


As we noted, the chipset hasn't really undergone any radical changes but rather has take a speed bump up a notch to a 533MHz "Quad Pumped" (133MHz Quad Data Rate) front side bus.  As a result, the specs are pretty straight forward and a picture tells the story just fine.

The i850E Chipset
Fat pipes, more bandwidth

Here we see the same feature set as the first revision of the i850.  The only change in this diagram is the 533MHz system bus.  However, word on the street is that Intel's "ICH4" chip is coming shortly, which should add a few more bells and whistles to the mix.  It will be interesting to see what the motherboard manufactures can put together with the i850E and the ICH4.  For this review however, we've tested the i850E driven Intel D850EMV2 motherboard and pitted it against some stiff competition, Abit's totally fabulous TH7II-RAID.

Intel D850EMV2




The D850EMV2 is a fairly well rounded board with on board AC '97sound, support for up to 5 USB 2.0 channels, hardware health monitoring, etc.  There is a version with on board Intel Pro/100 Ethernet support but we weren't fortunate enough to score that board.  Other than that, the D850EMV2 is a pretty straight forward quality board from Intel.  Enthusiast who want to overclock probably won't get too excited with this board however.  As with all Intel boards, CPU set up is done automatically and there are no available adjustments in the BIOS or with jumpers.

Finally, we should point out that the D850EMV2 does in fact support an FSB of 533MHz but will automatically drive any PC800 RDRAM module at 800MHz speeds.  However, if you are in possession of the currently "rare" officially rated PC1066 stick, with an on board SPD chip that tells the BIOS that it is a PC1066 module, the D850EMV2 will boot to PC1066 mode with a "not officially supported" warning.  Intel is not validating the i850E with PC1066 RDRAM until later this year.  However, that didn't stop us from finding another way to "skin a cat". 



Not long ago, we posted an article covering a chip level modification that we did to one of our Abit TH7II-RAID boards.  Although the TH7II-RAID comes equipped with Direct RAMBUS Clock Generators (DRGC's) that are rated for a 400MHz front side bus, running the board at 533MHz front side bus and the RDRAM at 1.066GHz (533MHz DDR), otherwise known as PC1066, caused us some serious instability.  Often times we couldn't even get the system to boot.

The limiting factor with some i850 boards, in getting your PC800 RDRAM to run at PC1066 levels, surprisingly, is not the RDRAM modules themselves.  Actually, most 8 chip 128MB modules or 16 chip 256MB Samsung modules, will run at PC1066 level with excellent stability.  What is holding you back most of the time, are the DRCGs themselves.

DRCGs and new TI DRCGs installed on TH7II-RAID

So, we had our stock PC800 DRCGs professionally replaced with Texas Instruments PC1066 capable DRCGs.  Some of our readers have reported in that in fact they have been running at PC1066 levels, with Pentium 4 1.6A chips, with the stock ICS DRCGs that are on the TH7II-RAID.  However, we haven't been so lucky and the only way we could get a stable system was to have the new TI DRCGs that handle 533MHz speeds, soldered on in place of the ICS parts.  For a skilled PCB rework technician (like the woman that worked on our board) this is a very easy remove and replace procedure.  However, it is not for the novice.

Regardless, the results were that we effectively took our stock Abit TH7II-RAID and turned it into an i850 board that was not only capable of the 533MHz front side bus (adjustable in the BIOS) but could also run our PC800 RDRAM at PC1066 speed, so we could see the full potential of the Pentium 4B processor.

We should also note that we have heard of other boards on the market, perhaps the Asus P4TE, that we have been told have stock 533MHz DRCGs installed.  Frankly, that would be a great option, if you can confirm that they are in fact on a particular board, before you buy it.  You'll see why in the following pages. 


Test Setup and Preliminary Numbers