Newbie AMD multiplier question

[Mark]

OK, I got all of my parts in to make the switch from Intel to AMD...but I have one last question before I put it all together. Is the multiplier for a 1.33 AXIA 266 CPU.....5, 266fsb/1330=5....OR....10, 133fsb(2x133=266 I know)/1330=10????? Thanks, I will let you know how it all turns out....Mark

[AMDGuy]

It will be 10 X 133 = 1330

AMD T-birds have a 133 FSB but an internal 2x making it an effective 266. Confusing I know.

[castle lager fan]

Mark,

AMDGuy is absolutely correct. It's 10x multiplier to get 1.33GHz. The reason they call it 266 MHz FSB (Front side bus) is that the data gets tranferred on the rising and falling edge of the clock signal, does giving an effective throuhput of twice the clock signal rate. Does AMD called it DDR (Double data rate) for it gets twice the throughput for the same clock rate. You will be able to get more info in tomshardware.com and jedec.com . Good luck and clock hard!

[taz1004]

Now, can anyone explain PC1600 and PC2100? :)

--BrianC

[Mark]

Thanks guys, I greatly appreciate the help and explanation. Mark

[AMDGuy]

taz1004 (Jun 05, 2001 03:32 p.m.):
Now, can anyone explain PC1600 and PC2100? :)

--BrianC

I'll take a stab at this....*tries to remember all the info on PC1600 vs 2100....

Basically it has to do with the data rate of the ram. PC1600 will pass 1.6GB of data in a certain time frame (can't remember the time frame off hand) and PC2100 will pass 2.1GB. Soon PC3200 will be out. It's kinda ridiculous. The easiest way to explain it is the difference between PC1600 and PC2100 is about the same as PC100 and PC133.

Hope this helps.

[castle lager fan]

PC1600 refers to 200 MHz DDR or 100 MHz FSB x2 for DOuble data rate. PC2100 is 266 MHz DDR.

The calculation is as follows:
Buswidth is 64bit thus 8Bytes between northbirdge and CPU. Thus you can get 8 bytes transported each clock cycle for normal SDRam. Now with DDR you can transport 16 bytes per clock cycle due rising and falling edge transfers. Take 16 bytes per clock cycle times 100 MHz for "200" MHz DDR and you get 1600MB per second transfer therefore PC1600 or 1600MB per second theoretical throughput. Do the same for the "266" MHz DDR and you will get 2100 MB per second.

I think on Samsung's website there is some good documents on memory, including RDRAM aka Rambus aka "we dont like". See tomshardware under CPU's and mainboard for some good articles on chipsets and ram, they also have NVIDIA's nforce their which looks pretty good on paper.

[taz1004]

Umm... I was semi-joking. :) Didn't think you guys would actually come up with explanation. Regardless of how they come up with the names, it all seems like marketing to me. PC1600 and PC2100 were originally planned to be named PC200 and PC266. And they changed it to make it sound better and faster than PC800 RDRAM. And someone had to be creative and come up with reason for naming it that way.

Same with Athlon4. Never saw Athlon2 and 3 before.

--BrianC

[castle lager fan]

It might be marketing, but there's thruth in the numbers. I agree that they should have just called DDR100 and DDR133 or something that is in line with what it meant on earlier systems instead of going from frequency to to transfer rate. But ah well!! Now if you want to know how rambus works...... see one of the websites I mentioned :-)