My FSB sucks

[Banditman]

When I purchased my mobo and processor, I was under the assumption the the mobo I purchased would allow the full speed of the 4000+ of 2 ghz FSB but was dooped when I got it to find out that it only run at 1 ghz. I was just looking for a mobo that would accept the 2 ghz FSB and still support the AGP slot. I found this site: GIGABYTE GA-K8U-939 Socket939/Uli1689/FSB2000/AGP/ Motherboard . Now that is the EXACT same mobo that I have. How can it support 2 ghz when mine does not? I went to Gigabyte's site and looked up the bios updates and the latest is F5 which I have and no mention of FSB updates. I tried to increase the FSB in bios but it will only go to 1 ghz. there must be a way to increase the FSB without buying a new mobo according to that web site. Anyone know how?

[Lead Head]

Originally Posted by Banditman

When I purchased my mobo and processor, I was under the assumption the the mobo I purchased would allow the full speed of the 4000+ of 2 ghz FSB but was dooped when I got it to find out that it only run at 1 ghz. I was just looking for a mobo that would accept the 2 ghz FSB and still support the AGP slot. I found this site: GIGABYTE GA-K8U-939 Socket939/Uli1689/FSB2000/AGP/ Motherboard . Now that is the EXACT same mobo that I have. How can it support 2 ghz when mine does not? I went to Gigabyte's site and looked up the bios updates and the latest is F5 which I have and no mention of FSB updates. I tried to increase the FSB in bios but it will only go to 1 ghz. there must be a way to increase the FSB without buying a new mobo according to that web site. Anyone know how?

The HTT Bus runs at 200Mhz, but is penta? pumped to 1Ghz, but it can do 2000 Megatransfers/s. Which is where they get 2Ghz, Don't worry, everythings working fine as it should

[Zambini]

Don't mean to hijack, but what is the difference between Bus Speed and Rated FSB?

my bus speed is only 400mhz but my Rated FSB is 1600 mhz.

I guess thats a similar question to his original?

[Lead Head]

Originally Posted by Zambini

Don't mean to hijack, but what is the difference between Bus Speed and Rated FSB?

my bus speed is only 400mhz but my Rated FSB is 1600 mhz.

I guess thats a similar question to his original?

Its called bus pumping. I'm not entirely sure how it works, but your bus is "quad pumped". I know doubled pumped the data is transmitted on the rise and fall of each clock cycle.

EDIT: Quad Pumped means that data is transmitted on the Rise, Fall, and Zero of each clock cycle, opposed to only on the peak of single data rate buses

[Reloadron]

Originally Posted by Zambini

Don't mean to hijack, but what is the difference between Bus Speed and Rated FSB?

my bus speed is only 400mhz but my Rated FSB is 1600 mhz.

I guess thats a similar question to his original?

To further expand on what Lead Head is saying with respect to "Quad Pumped":

For example the Pentium 4 has a “400Mhz Front Side Bus”, but it is in fact 100Mhz ‘quad pumped’. This means that data is transferred twice per clock cycle, on the rising and falling edge (like DDR memory which will be mentioned later), and also transfers two bytes of data at a time to effectively give four times the throughput of a 100Mhz front side bus. How fast your processor runs at is determined by applying a clock multiplier to the frontside bus speed. For example, a processor running at 550MHz might be using a 100 MHz FSB; this means there is a clock multiplier setting of 5.5, thus the CPU is set to run at 5.5 times the MHz speed of the front side bus: basically equating to 100 MHz x 5.5 = 550 MHz. Athlon processors are available in multiples of 100MHz, 133Mhz, 266MHz 333MHz and now with the AMD K8 3200+ and AMD Athlon64 FX-51 1600MHz FSB.

What is FSB? Front Side Bus Info

This is where the term "Effective" comes into play with respect to the actual clock speed. Early systems would transfer data only once per clock cycle on the leading edge. That was a real number. However as things evolved more data could be transfered per clock cycle providing and "Effective" data transfer rate for the same actual clock frequency.

This is a good explenation of DDR SDRAM and should help put the picture together:

DDR SDRAM - Wikipedia, the free encyclopedia

At one time Corsair had an excellent online presentation but it seems to have been removed from their website.

Ron

[One4yu2c]

Part of the confusion here is that the A64 architecture doesn't have a true 'frontside bus.' Because of this, and how the architecture works, old terms get recycled and confused. Let's see if we can simplify things a tad:

HyperTransport
What you're seeing at 1GHz is the HyperTransport bus, which is how the processor and chipset bantor back and forth. It's a bi-directional link operating at 1GHz in each direction (800MHz on s754 processors), giving it an effective speed of 2GHz (1.6GHz on s754 processors). Most motherboards are going to report the real frequency, whereas from an advertising standpoint, it sounds better to tout the effective speed.

To break it down (and confuse) even further, that 1000MHz is derived from the base frequency multiplied by the HTT multiplier (x5 by default). This works out to 200 x 5 = 1000MHz (2000MHz effective).

Processor
Your processor, on the other hand, runs at the base frequency multiplied by the CPU multiplier (not to be confused with the HTT multiplier), which varies from processor to processor. Your 4000+ comes with a x10 multiplier, so it works out to 200 x 10 = 2000MHz.

What you've come to recognize as the frontside bus is really that 200MHz base frequency.

[Banditman]

Originally Posted by One4yu2c

Part of the confusion here is that the A64 architecture doesn't have a true 'frontside bus.' Because of this, and how the architecture works, old terms get recycled and confused. Let's see if we can simplify things a tad:

HyperTransport
What you're seeing at 1GHz is the HyperTransport bus, which is how the processor and chipset bantor back and forth. It's a bi-directional link operating at 1GHz in each direction (800MHz on s754 processors), giving it an effective speed of 2GHz (1.6GHz on s754 processors). Most motherboards are going to report the real frequency, whereas from an advertising standpoint, it sounds better to tout the effective speed.

Oh ok. Now I understand

Originally Posted by One4yu2c

Processor
Your processor, on the other hand, runs at the base frequency multiplied by the CPU multiplier (not to be confused with the HTT multiplier), which varies from processor to processor. Your 4000+ comes with a x10 multiplier, so it works out to 200 x 10 = 2000MHz.

What you've come to recognize as the frontside bus is really that 200MHz base frequency.

I think I can bump the CPU multiplier up to x12 in my bios if I remember correctly. What will the results be if I did that? Unstableness??

[One4yu2c]

Originally Posted by Banditman

I think I can bump the CPU multiplier up to x12 in my bios if I remember correctly. What will the results be if I did that? Unstableness??

Unless you have a rare Engineering Sample, non-FX Athlon 64 processors are multiplier locked, meaning you decrease the multiplier but you can't increase it. If you try to select a higher multiplier in the BIOS and save the changes, it will go back to default (x10), go under default, or just refuse to boot (not likely).

[Lead Head]

You never know One 4, maybe the planets are in the proper alignment for him to raise the multiplier

[simple_inhibition]

actually the default multiplier for the single core Athlon 64 4000 is 12x (for 2.4ghz) a 10x multiplier is found on the Athlon 64 3200 or X2 3800 (For 2.0ghz)