speed- what is it really?

[darkmatter]

I'm extremely confused. CPU speed is a function of FSB X the multiplier. I'm well aquainted with this notion. I've been pushing the limits of these two variables with my Athlon XP 1700+(11X133=1.47) for some time now. It's fairly stable at 1.96 (13X151). But XP's are available in bus speeds of 333 and 400 MHz. A 333 2600+ with a stated clockspeed of 2.08 should run much faster than that. The multiplier for a 266 (133) 2600+ is 15.5. But if the same multiplier is used for the 333 (166) FSB version you get 2.58. For the clockspeed to be 2.08 the multiplier must be 12.5. Does the multiplier decrease accordingly in a 333 CPU? A second question: When a FSB overclocked system crashes is it the CPU or the memory that fails? Or, if a 333 bus speed processor is put into a motherboard intended for 266 FSB can that system be FSB oc'ed more reliably than the original 266 CPU? I need a new processor. I was going to buy and unlock a 2600+ 266. But the Upgradeware XP-TMC socket adapter allows you to run any new XP with 333 or 400 MHz FSB speed. My mobo allows the FSB to be set from 100 to 200. If I buy a 2600+ at 333 FSB will I have more capacity to oc the system than with a 266 FSB? The stated clock speeds of both FSB versions of the 2600+ is 2.13. Which has the greater capacity for speed? I assume the 266 version would be pushing the FSB barrier more than the multiplier and the 333 would be pushing the multiplier more than the FSB to attain the same increase in speed. I know this is a lot but I'd appreciate ANY help.

Thanks

 

[pIII_Man]

Yes the multiplyers are diffrent from cpu to cpu.

About fsb overclocking...if you can reach a higher speed by overclocking via multiplyers than via fsb...then yes it is memory example:
150mhz x 12= 1800
133mhz x 15 = 1995
if these are the max overclocks 1 is done by changing multiplyers and the other via fsb...in this example memory is holding the cpu back...because the cpu obviosly can handle more than 1800 mhz but the memory cannot hande more than 150...although there are other factors such as the chipset and agp/pci bus speeds

And finally about the upgradeware adapter...just buy a new board...sure with the adapter you can run the cpu at its rated speed...but the bus speed will be slower...and the bus speed is very important as the cpu will not have much memory bandwith...seeing as nforce2 boards are only $80 its just not worth it IMO.

And about your final question what mobo do you have?

There is no smell better than fried silicon

 

[darkmatter]

My motherboard is an ePox 8KHA+. I think it will take all of the current athlons as is but the adapter automatically unlocks the multiplier and let you set DIP switches to select a multiplier up to 24. I do not relish the idea of doing the whole exacto knife/scotch tape, epoxy and liquid solder thing again to unlock a new athlon. I made a huge mess getting my current one unlocked. But the main need for the adapter is that the most current BIOS from ePox will only allow a multiplier of 16. To get the 3000+ up to its rated speed at 133 without FSB oc'ing I'll need a huge multiplier (not that I have any intentions of buying a Barton core). But I would like to see how fast I can get a 2600+. I have no monetary objections to buying a new mobo but I have many, many doo-dads connected to my system. A lot of audio video stuff to an ATI AIW,a very finicky Turtle Beach sound card and a music server. I DO NOT want to go through the nightmare of setting all that up to work together ever again (until the AMD 64 comes out anyway). So, I guess what I'm most interested to know is- with my mobo in mind, does buying a 333 MHz CPU has any advantages or disadvantages over the 266 flavor.

 

[pIII_Man]

Well your board will take most of the current athlons...with exeption to the 200mhz (400mhz ddr) athlons. I was under the impesion that you owned an older board...but yours is fine for a 333mhz cpu. What are the advantages of 333mhz bus...Faster memory speed...and therefore more bandwith it does help quite a bit. Your board WILL support a new 3000+ barton (only the 333mhz fsb version) as this barton is using the 333mhz (166 sdr) bus. This barton uses a 13x multiplyer and 166mhz (sdr) bus.

With good memory and cooling you 1700+ should hit 2.1-2.3 ghz...however this is only if you have a tbred B. A new 2600 should clock about the same...so if you have a tbred B save your money on a new heatsink instead of a new cpu.


There is no smell better than fried silicon

 

[darkmatter]

To be honest I don't really know what breed my athlon is but it hasn't gone above 1.89 reliably. The temps stay low (I bought a TTake Volcano 7 some months ago) but unfortunately the highest I can get the multiplier is 12.5. The FSB max is 151. The system still hangs occasionally but not enough to make me change the settings. So, I'm thinking it's got to be the tbred A. I don't remember having a choice at the time I bought it in August of 2001(and I did a lot of reading) so I'm pretty sure its the first version. I've got 512MB of Samsung PC2100 RAM. Not the best but still disappointing that it will only go 18 MHz faster than it's rated. If I'm going to change the bus to 166+ MHz I should probably upgrade to a faster, better quality RAM. Do you think?

 

[pIII_Man]

sounds like a tbred A in my opinion...any tbred B should at least get 2.0ghz...and that would be a very bad one...have you tweaked the voltages any...if not try raising them a bit. I still would not go for the 2600 if you are going to overclock...the 2100 will yeild very similar overclocks. I would also no splurge on a barton as your chipset probably will not support fsbs over 175mhz although the option may be there in the bios the chipset probably won't take it. So your best bet for overclocking is a 266mhz bus cpu.

There is no smell better than fried silicon

 

[darkmatter]

Yeah, I've tried changing the volts both the CPU and RAM. The best setting seems to be +.05 and +.025. I read the Tom's review on the barton and think I would pass even if my board would do it. Doesn't seem to worth an extra $150-$400. I'd like to get a 2500 or 2600 for the FSB improvement. I've pretty much decided to get a stick of quality PC2700 anyway since my current stuff doesn't seem to be up to snuff. Thanks for all you advice!