65 w tdp vs 95w

[valhallarising]

what difference in temperature is expected if i got to identical cpus one with 65 w and one with 95 w?
for example . intel core quad q8400s 4x2.66 GHz compared to intel core quad core q8400 same cpu but with 95 w? will there be a big difference in heat under load or just a few c? thanks

 

[kanewolf]

It would depend on the cooling. A large air cooler capable of handling a 200W CPU would have little impact. The stock 65W cooler might not handle it.

 

[valhallarising]

lets say the cooler in this case is on the weak side but rated for 95 w tdp , shouldnt the 65 w tdp cpu run cooler even on load?

 

[spdragoo]

Hard to say. So far, aside from the TDP difference, the only other differences I can confirm are that the Q8400S has a higher operating temperature (76.3 C, http://ark.intel.com/products/42112) than the Q8400 (71.4 C, http://ark.intel.com/products/38512), & that the Q8400S tends to cost more (started off ~$50USD more). I think it's strange that the chip with the lower TDP has the higher thermal limit, & I don't know if that means it uses less power while running hotter or if it means something entirely different.

Generally, I tend to avoid the CPUBoss site for comparison purposes, but interestingly enough they show both air- and water-cooled OC speeds for the Q8400, but not for the Q8400S (http://cpuboss.com/cpus/Intel-Core2-Quad-Q8400S-vs-Intel-Core2-Quad-Q8400). Don't know if that's because the Q8400S wasn't as common, if it's because people that OC'd the Q8400S didnt' share their results with CPUBoss, or if it actually means that the Q8400S can't be OC'd. I've had trouble finding any definitive links about it.

 

[valhallarising]

yes that is strange, i will get some of them soon and try it. im hoping for some lower temps in some computers im upgrading. if you can call q8400 a upgrade.

 

[James Mason]

The S is a lower powered one, so it will perform worse, but it's higher heat tolerance is because it can't be pushed as hard, but is designed for an environment where the cooling isn't as good.

 

[valhallarising]

so the same specs at lower tdp performs worse? i thought the performance was the same no matter the tdp?

 

[valhallarising]

how much worse will the q8400s perform? in test they look to have the same score

 

[James Mason]

They're both pretty old and outdated, and it seems like "internally" they don't know they're different CPUs, so if you benchmark one, they just show up as Q8400.
SO the low end benchmarks are possibly the q8400s and the higher end are the OC'd q8400.

 

[valhallarising]

well the benchmarks looks the same, also rated the same on gaming performance but maybe they are wrong

 

[James Mason]

well the benchmarks looks the same, also rated the same on gaming performance but maybe they are wrong

I can't find any benchmarks to compare them really. I can find plenty for the Q8400, but almost none for the S.
Don't be fooled by spec sheets, they're not really, straight forward.
Lower power pretty much always equals worse performance, especially for the same model of CPU.

 

[valhallarising]

Another cpu i tried is intel xeon x5450 120 w tdp and intel xeon e5450 80 w they are almost the same and they perform about the same, so in that case it dont seem to effect the performance.

 

[James Mason]

Ah I see , well in the Xeon's case there, the Es are a bit higher quality, so while their specs are the same, they can run at higher speeds and at lower watts/tdp. The Q8400/S is probably the same situation then.

You won't find this very often with modern CPUs though, so don't think the same will apply if you go for a i7-7700t

 

[valhallarising]

i guess i will find out, im replacing a q6600 with this just for the lower heat. im hoping at least this is as good as a q6600 when it comes to the performance or it was a big mistake to buy them. from what i can see the q8400s cost more than the q8400 when they was new so maybe the performance is the same.

 

[James Mason]

Yah, the q8400 is definitely a little bit better than the q6600.

 

[valhallarising]

so you Think the q8400s still will beat the q600 even with the 65 w tdp? thanks

 

[spdragoo]

In terms of temps, yes, it should beat it. You probably won't see much improvement in overall performance, but their lower TDP (even the Q8400 has a slightly lower TDP than the Q6600) should help them run cooler.

Not quite the same chip, but in this review of the Q8200S (http://www.legitreviews.com/intel-core-2-quad-q8200s-processor-review_896), they compare the chip to its 95W TDP Q8200 sibling, & basically that the "S" series were geared towards OEMs building small form factor PCs (i.e. PCs that, with a combination of lower power draw & a higher max operating temp, would handle the lower air flow & higher change of elevated temps for that size of system). Good news, too, was that they were able to OC their Q8200S (per page 13 of their review, with their motherboard they managed to get to just over 3GHz with a 430MHz FSB/x7 multiplier on stock voltage, & DDR3 RAM was bumped up to 1600MHz; with voltage increases, they were able to bump that up to 3.15GHz & a 450MHz FSB/x7 multiplier, which let them bump the DDR3 up to 1800MHz. They mentioned being able to hit 475MHz on the FSB, but that was pretty much a wall even with watercooling & higher voltages).

I would say, if you can get the Q8400S, get it, because it'll run cooler & has a higher thermal margin than the Q8400. Plus, depending on your motherboard you'd have the option of OCing it.

EDIT: This page (https://hothardware.com/reviews/intel-core-2-quad-q8400s1?page=2) talks about OCing the Q8400, which is apparently very similar to the Q8200 (same FSB, just a x8 multiplier for the faster CPU frequency), & they were also able to get to 400MHz FSB before having to increase voltage (bumping it to 3.2GHz), & hitting a similar wall at 490MHz (3.92GHz for the CPU), although that wall apparently didn't involve out-of-range voltages or "more powerful" cooling (possibly meant they were only using air cooling?).

 

[valhallarising]

thanks , im upgrading a few Fujitsu bxt computers, i got the q8400 s for 16 s each so it can be Worth it if get the temperature down. right now with q6600 75-78c under load if i can get that down 10 c it would be a good deal.

 

[valhallarising]

i just tried the q8400 s and it got the idle temps down to 35-40 and load temps to about 55-60 . when it comes to performance the q6600 almost was better together with a geforce gtx 960 . with q6600 about 40-45 fps battlefield 1 full hd with q8400s about 30-35 fps but it seems very smooth so good results after all.
im guessing the tdp does make a difference when it comes to performance.

 

[Ecky]

TDP makes no difference in performance with these older CPUs. TDP is "thermal design power", which mostly describes the type of heatsink you need to use with the CPU. A 65w Q8400 and a 95w Q8400 both have the same clockspeed, the 65w version is just a better CPU, binned because it can run at the same speeds with lower voltage, thus producing less heat. Intel sold them at a higher price because they were examples of better silicon, and often the lower TDP parts could overclock higher.

If you're seeing lower performance with a Q8400 vs Q6600, something is wrong. The Q8400 has better performance per clock and higher clockspeed, so all else being equal, it should perform better in every scenario, if only marginally.

 

[valhallarising]

the performance seems slightly better with the q6600 , so your saying that higher tdp shouldnt affect performance only heat? the opinons seems very different about that.
im gonna try a Clean install windows and see if i can get alil better performance becuase i had a blue screen crash right after installing the new cpu. still the performance is decent and the temperatures is very good now. much cooler and more quiet system.
if you buy this cpu make sure you got 1066 mhz ram because my crucial 1333 mhz ram that worked with the q6000 didnt boot with this cpu, i had to change it for samsung 1066 mhz ram.

 

[Ecky]

For these particular CPUs, TDP doesn't affect performance. On newer chips which have turbo, higher TDP parts often turbo at higher frequencies for longer periods (especially in mobile).

 

[valhallarising]

ok thanks ecky, good information. for some reason the q6600 seem to push out a few more fps but it seems more smooth with this cpu.
got the temps down and gets about 30-50 fps with geforce gtx 960 in full hd . i guess the gpu could be running with double horsepower paired with better cpu though