Whoa, did I miss something...question about the KT133 chipset.

[The Sauce]

Can you clock the memory independently of the FSB to 133 MHZ? I just saw someone say something to that effect in a thread. Is it true?

Secondly someone said that the new bios on the MSI mobo accepts the new AMD 133 CPU's...is that to say that the chipset can be clocked to 133?

 

[ViRGE]

To answer your first question; we've been able to set the memory speed semi-independently of the FSB for a while now with VIA chipsets. Check out a KX133 based board; they all can run their mem at FSB, FSB+PCI, and FSB-PCI. It's really not major news.:Q

 

[LXi]

<<Secondly someone said that the new bios on the MSI mobo accepts the new AMD 133 CPU's...is that to say that the chipset can be clocked to 133?>>

Nobody knows enough about this BIOS update yet. But I can tell you that this BIOS update allows the 133MHz Tbirds to operate on the MSI board, but will it run at 133MHz? That would be very hard to answer.

 

[The Sauce]

Ok...so if I understand correctly, FSB + PCI = FSB (100 MHz) + PCI (33 MHz) = 133. Correct? So memory could be run at 133 even now?

And if you clock the FSB up to 110, per se, memory could run at 143?

If that's the case, then what's the big deal about the new 133a chipset? You'd wind up with pretty much the same thing. All your periphs would be running at the same speed (133/4) and memory at 133, and proc at whatever you want. Am I missing something here?

 

[LXi]

<<Ok...so if I understand correctly, FSB + PCI = FSB (100 MHz) + PCI (33 MHz) = 133. Correct? So memory could be run at 133 even now?
And if you clock the FSB up to 110, per se, memory could run at 143?>>

First of all, you need to get your calculations correct. Its +33%, not +33MHz. So if your FSB is 100MHz, your RAM would be 133MHz(100x133%=133MHz). If your FSB is 110MHz, your RAM will run at 146MHz(110x133%=146MHz).


<<If that's the case, then what's the big deal about the new 133a chipset? You'd wind up with pretty much the same thing. All your periphs would be running at the same speed (133/4) and memory at 133, and proc at whatever you want. Am I missing something here?>>

Yes you're missing something here. The main thing about KT133A is not the speed of the PCI bus, not the speed of the AGP bus, not the speed of the RAM. It's the speed of the FSB. KT133 is known to be unable to perform above 110MHz, but KT133A allows it to go to 133MHz therefore being compatible with 133MHz Tbirds and ensures they run at 133MHz. This has nothing to do with PCI, AGP nor RAM bus.

 

[WetSprocket]

I guess the big deal would be being able to run the EV6 bus at 133(DDR). Since most Athlon based systems cant hand more than 110 it may be possible to have a better fsb overclock.

 

[The Sauce]

You da man, Lxi. So what I guess it comes down to then is what is the real world difference between a 100 MHz clocked chipset and a 133 MHz clocked chipset, with all other components being run at identical speeds? I would not have guessed that this would be considerable.

 

[LXi]

<<So what I guess it comes down to then is what is the real world difference between a 100 MHz clocked chipset and a 133 MHz clocked chipset, with all other components being run at identical speeds? I would not have guessed that this would be considerable.>>

It also allows overclockability, reviews are showing the KT133A capable of taking the 100MHz Tbirds up to 133MHz with ease. And yes, the PCI bus, AGP bus, and RAM will run at appropriate speeds depending on the front side bus.

 

[The Sauce]

<< It also allows overclockability, reviews are showing the KT133A capable of taking the 100MHz Tbirds up to 133MHz with ease. >>



Ok...you lost me again. Why can't you overclock the processor to the same speed just by increasing the multiplier and forget about the FSB? (i.e. what's the difference between 7.5 x 133 and 10 x 100?). You'd still have the CPU overclocked the same. How does increasing the FSB to 133 help to overclock the TB when you can adjust the multiplier to whatever you want?

 

[ViRGE]

Because depending on how you got your CPU, unlocking it may not be a good option.:Q

 

[LXi]

<<Ok...you lost me again. Why can't you overclock the processor to the same speed just by increasing the multiplier and forget about the FSB? (i.e. what's the difference between 7.5 x 133 and 10 x 100?). You'd still have the CPU overclocked the same. How does increasing the FSB to 133 help to overclock the TB when you can adjust the multiplier to whatever you want?>>

Yes, that is absolutely true, BUT, increasing the FSB speed will greatly increase performance. A Tbird 1GHz running 100MHz at FSB(100x10=1000) will definitely run slower than a Tbird 1GHz running at 133MHz FSB (133x7.5=1000). If you have a Tbird 750MHz(100x7.5), it may be wise to overclock with Front Side Bus instead of multiplier, because of the performance difference.

Check this article out.

 

[Insane3D]

Just to add to what Lxi said, when you overclock via the multiplier, you are overclocking the CPU only. When you overclock via FSB manipulation, you are overclocking everything, PCI, AGP, etc. Also, the faster the FSB is running, the more bandwith the CPU has to move information to and from the rest of the system. I hope that makes sense.

 

[The Sauce]

<< When you overclock via FSB manipulation, you are overclocking everything, PCI, AGP, etc. >>



It was my understanding that if you ran your FSB at 100, you had to use a /3 divider for the PCI components giving you 33 MHz, and if you ran the FSB at 133, you had to use a /4 divider for the PCI to keep it at 33...so I dont understand your comment about the PCI, AGP, and all other components running faster with the FSB at 133...really they shouldn't....from what I understand.

Now obviously if you go from 133 -> 140 and keep the divider at /4 then you are overclocking everything else, that I understand...but that's not what I am asking about.

So if I am right (and I may very well not be), by clocking the chipset to 133 with the new chipset, the only advantage you are getting is a faster chipset, not PCI, not AGP, not memory, not CPU.

What LXi is saying is that there is a great difference in performance with just increasing the chipset speed and nothing else. I've never actually seen that stated before....or tested...but I believe him. I was under the impression that the main performance hit that everyone wanted 133a for was to get their memory up to 133. And i didn't realize you could already do that with the KT133.

 

[The Sauce]

Maybe to settle the matter, I'll wait for the new chipset to come out and run some benchmarks to see what the difference really is.

 

[Noriaki]

Insane3D is right if you run at a non-standard FSB

But on the KT133A 133Mhz is a standard FSB so all other things are the same.

7.5x133 = 10x100 = 1000Mhz but the 133Mhz FSB will give the first one an edge. Not sure how much of an edge, but everything else is equal that one attribute is faster so overall you'll get a boost, might be slight, might be alot.

 

[Dulanic]

The reason you get better performance with the high FSB even with the same PCI memory etc.... is... hummm here is a way too put it.... You have 2 cars... equal in power... (The CPU) and you have 2 tunnels one 10 feet wide and one 13.3 feet wide (The bandwith from the higher FSB). Which can you drive faster in? Obviously the 13.3 foot wide tunnel.

Anyways the faster the FSB the more bandwith there is between the CPU and EVERY other device in your PC.

 

[The Sauce]

Ok, last question, I promise!

What good does it do to run your memory at 133 on the KT133 (FSB+PCI) if it being transmitted across a FSB running at 100?!? Is this just a gimmick by VIA to make people think they are getting faster memory performance? If it all depends on the FSB speed then why even bother running your memory faster?

 

[Dulanic]

Because... running memory at a higher clk frq just gives it more bandwith.... however the FSB bandwith is still higher then even the memory running at 133. Your thinking in terms of Mhz not actual bandwith

 

[Dulanic]

And remeber the EV6 bus (Athlon FSB) is effectively 200Mhz because its DDR.

 

[Haervii]

Is Kt133A a completely different chipset with completely different motherboards that hasn't come out yet?

 

[LXi]

<<What good does it do to run your memory at 133 on the KT133 (FSB+PCI) if it being transmitted across a FSB running at 100?!? Is this just a gimmick by VIA to make people think they are getting faster memory performance? If it all depends on the FSB speed then why even bother running your memory faster?>>

It gives you better memory performance, its simple as that. Whichever is clocked higher will get speed advantage. The best would be having both FSB and memory running at 133MHz. If you cant run FSB at 133MHz, run your RAM at 133MHz to get something out of nothing.

Back to the PCI/AGP divider thing. Its actually very easy to understand, the objective is to try to keep the PCI bus as close to 33MHz as possible, and AGP bus as close to 66MHz as possible. If your FSB is 100MHz, the PCI bus divider will be set to 1/3(of the FSB speed), so it results 33MHz, the AGP bus divider will be set to 2/3(of the FSB speed) so you get 66MHz.

Now, if you increase your FSB to 110MHz, you'd also increase your PCI and AGP, because 110x(1/3)=37MHz PCI, and 110x(2/3)=73MHz AGP bus. You see how you overclocked your PCI and AGP bus as you overclock your front side bus?

Overclocking to 133MHz, or running a 133MHz Tbird will require a different set of dividers. Because using the old 1/3 and 2/3 dividers for PCI and AGP will result a bus that is too high for any PCI(133x(1/3)=44MHz) and AGP(133x(2/3)=89MHz) component to take. You see how that works? With 1/4 PCI divider, and 1/2 AGP divider, you can get them to run at 133x(1/4)=33MHz and 133x(1/2)=66Mhz respectively again. Does that clear things up?

 

[The Sauce]

Yah, I understood all that FSB/AGP/PCI overclocking stuff...been doing that for years. What i didnt understand is the following: your memory is not doing any processing or calculations...its just receiving data and sending data. It does this via the FSB to wherever that data is being sent to. Now if the memory can fetch and send data at 133 MHz, but only through a FSB that is running at 100 MHz, what good does that extra 33 MHZ do for it?

The way this was explained here is that the EV6 bus is DDR, and so is effectively a 200 MHz FSB...is that correct? Am I confusing MHz with bandwith? Is the FSB a wider path than the memory? If so then this all makes sense.