Athlon 64 3800+: FSB running @ 200 Mhz--wtf?

[mericm]

PCMark 04 stated the FSB for my Athlon 64 3800+ (2.4Ghz) was running @ 200 MHz (Cool-N-Quiet also states this). This CPU is advertised as running @ 2000MHz or 2.0GHz--what gives? That's a big difference if true or is there some nonsensical geek created multiplier I'm not taking into consideration? It seems to me to be fast (I can only compare it to an Athlon 64 3200+ I had before). So why don't these benchmark and system info programs display 2000 Mhz FSB? Please give me a coherent explanation--even if it means telling me I'm an ignorant fool for not knowing this! Thank you.

 

[mericm]

System specs for all you wanna-be gaming rig builders

Compaq GX5050 X-Gaming Tower (refurbished)
CoolerMaster WaveMaster Aluminum Tower
Enermax 470 W Noisetaker PSU
MSI K8 Neo nForce3 Ultra (939-pin) mobo
Athlon 64 3800+ CPU
1024 GB Dual Channel PC3200 DDR RAM (4 256MB sticks: 1 pair Samsung, 1 pair Kingston)
200 GB Seagate Barracuda SATA HDD
ATI Radeon 9800 XT 256MB AGP video card
Creative SB Audigy 2 ZS sound card

I got all this for $700 @ compusaauctions.com! I spent $250 upgrading the video card and adding 512MB RAM for a total cost of $950! The stock nVidia GeForce FX 5700 256MB card absolutely sucked and the added memory has added increased spend w/ online gaming. So check out the website for great deals--even though all the GX5050s are gone--they might have some more later, and by the way I got the refurbished Radeon 9800 XT for only $129+ $20 shipping @ the same website. This card still lists for @ least $350 new!

 

[amazon_sephy]

hey mericm,

I think you seem to have a few things confused. You said you have an athlon 64 3800 which is 2.4ghz, and you said it was rated at 2.00ghz? Its supposed to be 2.4ghz which is probably what you meant. The second thing is that no cpu has an fsb of 2000mhz that i know of. Athlon 64's have their memory controller built on the chip i believe, and thus technically dont have fsb's, but their memory controllers are rated at 1600mhz, -edit, some of the newer boards, like yours, appears to be 2000mhz. Basically its not important to know this value like it is on the intel processors. The reading of 200mhz your getting sounds like the ram speed to me. Im assuming your using ddr400 which is 200mhz *2 (400mhz equivilent) because its "double data rate" ram. Hope this clears some confusion up.

 

[mericm]

Yes--sort of. . .yippee!

According to Cool-N-Quiet, my PC is running @ 200Mhz X 12 which makes the processor speed 2.4Ghz--right? I thought maybe the FSB was separate from processor speed--so I am an ignorant fool. :giddy: I did see where the RAM was running also @ 200Mhz which confused me further since it is PC3200 (400Mhz) DDR--you're explanation helps a lot (i.e it's Xs 2 b/c it's double data rate) and now this stuff is making sense

 

[Didou]

First of all, there's no FSB on Athlon64s. You have a system clock which is used to determine the HyperTransport link speed, the memory speed & the CPU's speed. The system clock is almost always set to 200mhz (unless you overclock). You will then have a 1x multiplier for the ram (if you're using PC3200), a 4x/5x multiplier for the HT link (depending on if your chip supports a 800mhz or 1GHZ HT link) & 12x for the CPU speed.

PCMark is only reporting the speed of the system clock.

 

[Justin]

Didou wins


And is quite correct. The A64s have a much more direct communication link with memory than the previous athlons, so it can be confusing to people who aren't used to it. I myself was a bit confused when I first got my A64 3400+.