845 Chip VS 850 Chip problem

[dougry]

Okay, I'm confused. All the motherboards I have looked at tigerdirect and newegg with the 845 chipset can offer a 800Mhz frontside bus but only offer DDR400 memory. Therefore choking the FSB. And the 850 chipset with PC800 memory only offer a 400/533 FSB. Thefore choking the memory speed. Am I just misinformed about this? Or should a motherboard with a 800Mhz FSB also have memory with PC800?

Example. The motherboard I am looking at here offers an 800/533MHz FSB but memory is Single/Dual Channel DDR 400. Why 800 FSB but DDR400?

If I am confused about the FSB/memory bus relationship. Would someone please set me straight

[pixel]

I think you have just been misinformed as all motherboards work in this way.

I don't know if the memory speed effects the cpu speed, or vice versa.

If anyone could clear this up for me also.

I have never heard of a 850 chipset, I have only heard of the 845, 865 and 875.

Personally I woud tell you to stay clear of anything before the 865PE chipset, just performance wise.

[obiron]

I agree with pixel's sentiments about the 865PE chipset. I believe the 850 and 860 Intel chipsets support dual Xeon processors. My system at work is a 2Ghz dual Xeon on an 860 chipset motherboard.

As for the FSB relationships: my understanding of this may be a bit shallow but from what I've read, the 800Mhz and now 1000Mhz FSB speeds are really marketing BS. The FSB on most of these MBs are running at 200Mhz. They advertise the higher speeds by using DDR ram to double the FSB speed and Dual DDR Ram to quad the speed. So, dougry, the MB you linked to in your post supports the 865PE chipset which supports Dual DDR Ram. If I'm not mistaken, DDR400 ram should be just fine here but I believe it's designation is PC3200. You could go to http://www.crucial.com and search there for the ram you need on that board. They also have a very good explanation of all these terms. It wouldn't hurt to peruse that site for some more in-depth info.

Hope this has been helpful

[pixel]

Thanks for clearing that up obiron.

I guess I didn't know about te 850 chipset because I've never really looked into dual processors.

dougry I use an 875 chipset, but for anyone else I would suggest the 865 chipset purely because it is cheaperand still has basically the same features (with the difference being the 875 has PAT technology, but only boosts it about 5%).
(You can also find 865PE mobo's with PAT technology unlocked, only the old ones though because Intel have now tweaked the 865 chipset to make it impossible to unlock.)

I'm sure an 845 would be okay, but I would only suggest at least the 865PE for working with video.

[ofbarea]

First thing to notice is that P4 CPUs are 4 times faster that the rated fsb speed. This means that a 100 MHz mobo will be rated at 400MHz. A 133 MHz mobo will be rated at 533 and the 200 MHz mobos are rated at 800MHz.

The old 845 and 845GL chipset runs at 100 MHz and, therefore these mobos are rated for 400MHz operation. Depending on the mobo these chipset could use DDR 200/266 or PC133 memory. Of course DDR memory interface was a lot faster than the PC100/PC133 counterpart. This chipset is still the best cost effective choice for the new Celerons. (IE: if you finds a Tyan firedragon very cheap go for it).

The newer 845PE, 845GE, 845GV, 845E and 845G runs up to 133 and are rated as 533. These chipsets use DDR333 and this is faster than the previous versions. Still this interface was EOL because of the new 865 chipset.

The 850 chipset family also ran at 100 MHz and it was rated for 400 speeds. This chipset use the now defunct Rambus memory at PC800 specification. This is something to avoid.

The 850E chipset ran at 133 MHz and it was rated for 533 speeds. This chipset use the now defunct Rambus memory at PC1066 specification. This setup is Very fast, very expensive and very un-cool. This chipset used to be the speed king of Intel P4 CPUs but it did not included USB2, SATA of firewire. This chipset is another one to avoid unless you got lots of money to spare. To get Hyper treading you will need the 3 GHz CPU.

If you really want to buy a new P4 CPU based machine get something with the new 875 chipset, 200 MHz quad pumped to the new rated 800 MHz. This chipset will use DDR400 memory (200 fsb x 2 = 400) in a dual channel fashion. This is really fast. Also you get SATA as a bonus and Hyper treading is standadard stuff even a 2.4 GHz CPU sppeds.

for more detailed info take a look at the following link: http://www.intel.com/products/desktop/processors/pentium4/index.htm