My question: Can I install CPU with FSB higher than motherboard’s FSB?
I have a 2-year old motherboard ASUS P4SE/U2 with Celeron 1.7GHz on it and I wanna upgrade to Pentium 4. The manual says the board can support up to 3.06+ GHz Pentium 4/Celeron Northwood/Willamette with FSB 400MHz. But the hightest speed CPUs listed on http://www.asus.com.tw/support/cpusupport/cpusupport.aspx for this motherboard are:
Well… yes, you can plug in CPUs that are designed to run at higher busspeeds without a problem. However, if you mainboard does not support FSBs over 100Mhz (= 400Mhz because of the quad pumped bus), your CPU will be running at a lower speed, as the multiplier can’t be set!
If you can’t set your FSB to 133 or 200Mhz, you may want to look into overclocking your FSB. If you can set the PCI/AGP divider to 1/4 (for 533) or 1/6 (for 800), you possibly could overclock the CPU FSB and still benefit from the higher FSB without running into problems. There’s no garantuee here, but I’ve seen it working on quite some older systems. It just depens on what your board can do.
BTW… if you can’t find a fitting 3.0 Ghz CPU, why not get an 2.6Ghz CPU? It’s not that fast as the 3Ghz model, but it still beats the crap out of the Cellie
Based on what the specs read above, I’d look for a 400MHz FSB P4, and skip the higher-end 533 chips unless you want a new mainboard. I think you’ll find the cache differences alone between the Celeron and the P4 make a HUGE jump in performance. The early P4 Celerons were poor performers; the long pipelines of the P4 core require decent size caches to keep the pipes full with instructions. The P4 class Celerons suffered greatly due to their smaller caches, which resulted in more idle time waiting for instructions, and more cache misses. I’d bet that a P4 at 2.6 or 2.8GHz would make you feel like you have a new machine.
Running a CPU rated higher than 400MHz FSB will not only run the CPU slower than rated spec, but may also cause additional issues (your mainboard may not support Hyperthreaded CPU’s). As for why your mainboard doesn’t list newer CPU’sas compatible, you answered your own question: It doesn’t support a 533MHz front side bus.
Thanks, that’s good news if I can really do that. Except that LoneWolf15 says something different.
As I mentioned in the first post, I’m interested in #3. 2.8GHz (800MHz) Prescott 1MB cache. #2-#5 all have similar prices while #1 is Â£30 cheaper.
Thanks, that’s what I already checked and posted in the original post.
I’m in the UK and it’s easier (and may also be cheaper) to find the CPUs #1-#5 listed in the original post.
I do not want a new motherboard.
Exactly! It takes 10 hours to convert a DVD to XviD with this Celeron 1.7GHz and people says it should only takes 2 hours with Pentium 4!
Now, what you say here is different from what Dee-ehn says.
You say that it could cause additional issues. Could you give some examples? Surely not supporting hyperthreading is not an “issue” as long as the CPU can run fine (this leads the the next question).
When you say CPU X is not support by motherboard Y, do you mean a) CPU X wouldn’t run at all OR b) CPU X would run but at the max speed supported by the motherboard Y? My understanding was that it’s (b) and Dee-ehn confirmed that it’s (b) but from your reply I gathered you mean (a).
Similarly, the reason the newer CPUs are not listed could be because they are not “fully” supported i.e., not all features are supported (based on Dee-ehn’s reply). Or maybe because they wouldn’t run at all (based on your reply).
Dee-ehn, LoneWolf15: could you confirm please?
If #3. 2.8GHz (800MHz) Prescott 1MB cache can run fine (as best as the motherboard can support) without a problem I won’t upgrade the motherboard.
As far as I know (mostly from my own experiences), these P4 CPUs will work on older boards just fine, as long as the settings are correct (powersettings). They will work on lower speeds and without HT enabled of course.
Recently I put a 2.8 Ghz Northwood with HT on an old i845 based board (with SDR memory) and it ran fine. Overclocked the FSB and it worked like a charm!
If you want to be really sure (as there’s no 100% garantuee), you might want to take your computer to a store and have it tried there. Find a good store btw… or else they’ll be selling you a new mainboard as well
Prescott uses a different voltage, so I’d be wary of putting ANY Prescott core cip on a board that doesnt explicitly support it.
Best chance, out of those you list, would be #4 - The 2.8 GHz northwood 533 - which if you cannot overclock the FSB at all, would run at 2.1 GHz - the 800 FSB models would run at half speed, if they run at all
CPU Speed: [Manual|1700MHz|2266MHz]
CPU Frequency Multiple: 17x <- (always fixed)
CPU External Frequency: [100/33|101/34|102/34|…|133/33|134/34|…|166/33]
Memory Frequency: [Auto|200MHz|266MHz|333MHz|400MHz]
CPU Vcore Set: Auto
CPU Vcore: [1.850V|1.825V|1.800V|1.775V|1.750V]
Underscored means current settings. Current CPU is 1.7GHz Celeron. I don’t know why there are only 1.7GHz and 2.266GHz there but if I change it to 2.266GHz the CPU External Frequency will change to 133/33 while other settings remain the unchanged.
Would the mainboard accept “#4. 2.8GHz (533MHz) Northwood 512K” or any of the Prescott models (tempted by 1MB cache)? I don’t quite understand those many 1xx/3x External Frequency options and why there is only fixed 17x for Frequency Multiple though.
Intel Multipliers have been hard-locked since the last days of the Pentium 1 and MMX.
AMD spat on their enthusiast base, when they too implemented ever more vicious locking.
the 1.7GHz Celeron runs at a Multiplier of 17x 100 clock - with dual DDR for a quad-pumped 400 FSB
The fact it offers 2266MHz (17x 133.3)
Suggests that you could use, at least unofficially, a 533 FSB processor.
Not sure if a Celeron can be expected to overclock to that level, and not sure if the chipset will - I’ve seen boards that offer values in bios that are well beyond the chipset’s stability limits.
I’d be very reluctant to put a Prescott on a motherboard that doesn’t explicitly support it though, but the 2.8GHz 533 FSB Northwood looks possible, if the motherboard will hold the chipset overclock (unless they updated the chipset - that happens).