Sandy Bridge Based Pentiums

[LOL_Wut_Axel]

The clock speed of the 2100 is not 19% higher. It is 11% higher.

My source is just as valid as yours; Intel clearly states that it supports the same instruction sets.

11% loss of performance to clock speed. 20-30% loss of performance to lack of HT.

Those factors alone place the Pentium at anywhere from 62.3% to 71.2% the performance of the i3. That would average out to 66.75% the performance of the i3, making the i3 almost EXACTLY 50% faster on average.

Now, that's all in an ideal situation. Clock speeds don't scale linearly and HT doesn't offer the 20-30% performance boost that Intel advertises.

Also, the Pentium may lose more performance from cache loss for obvious reasons.

I have 8GB of RAM in my PC. If I pulled out 4GB, I wouldn't see any real difference in performance. If I pulled 2GB from that, I'd take a decent hit to performance. If I took 1GB from that, I'd take a very significant hit to performance.

That's not exactly the same concept, though I do see what you're trying to say. In any case, it's extremely unlikely that the extra 1MB L3 cache will give it a performance boost of 11-15%. Most of the differences from the 2500K and 2100, if you look at the reviews, are because of the extra cores in the 2500K, and the higher clock speed.

Maybe someone could chime in. It'd be interesting to see the performance difference, if any, from the 2500K with two cores turned off. Then we could directly compare the difference that comes from having 4MB L3 and 6MB L3. I doubt it would be anywhere near 11-15%, though. It's not like the Pentium is cache starved, since it has 3MB L3 cache.

 

[DaveSimmons]

40 watts less power under load makes the G840 much nicer than an E8400 for desktop use if you care about noise and form factor. Less power = less heat = less cooling = less noise, and means it can run quietly in a smaller case.

I also paid much more than $87 for my E8400 back in 2008. So: progress.

 

[pantsaregood]

What are you talking about "the baseline?" The i3 is clocked at 3.1GHz. The Pentium I'm referring to is the G840. I don't have a source, I just did some basic math. Intel cites HT as increasing performance by up to 30%. I clearly stated that such a boost is unrealistic in common application.

Also, can we please stop saying "baseline?" In absolute terms, the Pentium G620 is 84% the clock speed of the i3 2100. The i3 2100 is 119% the speed of the G620.

HT giving a 20% boost (even that is unlikely) would place the Pentium at 71.2% the performance of the i3 2100. That's within spitting distance of 66.6%, which would mean the i3 2100 was 50% faster. This is all in reference to the G840, though.

G620 should perform (with your 20% figure) at 67.2% of what the i3 performs at. Again, dead on 50% boost. The cache will slow it down a bit more. No instructions need to be removed to cut its performance.

 

[LOL_Wut_Axel]

40 watts less power under load makes the G840 much nicer than an E8400 for desktop use if you care about noise and form factor. Less power = less heat = less cooling = less noise, and means it can run quietly in a smaller case.

I also paid much more than $87 for my E8400 back in 2008. So: progress.

Sure, but the G840 is priced as of now at $85. Horrible pricing, if you ask me. The G840 is around the same speed as the E8600, so in terms of performance (which is my main argument since we're talking desktops), not much progress.

 

[LOL_Wut_Axel]

What are you talking about "the baseline?" The i3 is clocked at 3.1GHz. The Pentium I'm referring to is the G840. I don't have a source, I just did some basic math. Intel cites HT as increasing performance by up to 30%. I clearly stated that such a boost is unrealistic in common application.

Also, can we please stop saying "baseline?" In absolute terms, the Pentium G620 is 84% the clock speed of the i3 2100. The i3 2100 is 119% the speed of the G620.

HT giving a 20% boost (even that is unlikely) would place the Pentium at 71.2% the performance of the i3 2100. That's within spitting distance of 66.6%, which would mean the i3 2100 was 50% faster. This is all in reference to the G840, though.

G620 should perform (with your 20% figure) at 67.2% of what the i3 performs at. Again, dead on 50% boost. The cache will slow it down a bit more. No instructions need to be removed to cut its performance.

Wait, wait, wait... where are you getting this 66.6% and this 71.2%? Where did those come from?

And from the get-go, I was using the G620 to compare because it's the only Pentium that's remotely well priced. I don't know why you're mentioning the G840 now.

 

[pantsaregood]

Sure, but the G840 is priced as of now at $85. Horrible pricing, if you ask me. The G840 is around the same speed as the E8600, so in terms of performance (which is my main argument since we're talking desktops), not much progress.

I was referring to the G840 the entire time.

I have no idea why the G840 is priced at $85. Intel's suggested price is $75 or so, and retailers usually sell at or below MSRP. It does perform similarly to an E8600.

The G840, at $85, is actually slightly better price/performance than the i3 2100. You get ~70% the performance for 66% of the price. That's what I'd call negligible. $75 would be a far better price point for the G840.

The numbers come from assuming perfect scaling.

G840 is 89% the clock speed of the 2100 and 80% the performance at an equal clock speed. 0.89*0.8=0.712.

Very crude, yes. It does show, however, that in an ideal situation, no instructions need to be removed to "gimp" the Pentium.

 

[LOL_Wut_Axel]

I have no idea why the G840 is priced at $85. Intel's suggested price is $75 or so, and retailers usually sell at or below MSRP. It does perform similarly to an E8600.

The G840, at $85, is actually slightly better price/performance than the i3 2100. You get ~70% the performance for 66% of the price. That's what I'd call negligible. $75 would be a far better price point for the G840.

Exactly. That's why I mentioned the Celeron G530 probably being on Newegg and other retailers for $50-55, since retailers are upping the price by $5-10 in comparison to MSRP.

Take the G530 at $55 and it makes sense; a whole lot of it. The Pentiums I don't think make much sense because the Athlon II X3 is faster in multi-threaded apps, plus you can OC on the stock cooler a bit.

Also, your calculations: in the review the G840 was around 10% faster than the G620. I don't understand your other calculations.

 

[StrangerGuy]

I'm not even sure where this L3 cache factor comes from, these pentiums have the same 1.5MB L3 per core like the i5s. Any differences has to be due to lower clocks and lack of HT.

Still, not a terribly exciting product but at least Intel didn't gut the power management out.

 

[pantsaregood]

I would expect the Pentiums to perform better than Athlon II X3s in the future. They have no support of SSE4.1/4.2. Intel's pricing makes sense when compared against other Intel products; AMD's low end just ruins that.

The Sandy Bridge Celerons and Pentiums could've used some differentiation. Single core Celerons with HT would've saved Intel money, resulted in cheaper products, and cause some significant differentiation between the Celerons and Pentiums. The Celeron G540 is 2.5GHz with 2MB of L3 cache. That's going to perform almost identically to the G620.

 

[LOL_Wut_Axel]

I would expect the Pentiums to perform better than Athlon II X3s in the future. They have no support of SSE4.1/4.2. Intel's pricing makes sense when compared against other Intel products; AMD's low end just ruins that.

The Sandy Bridge Celerons and Pentiums could've used some differentiation. Single core Celerons with HT would've saved Intel money, resulted in cheaper products, and cause some significant differentiation between the Celerons and Pentiums. The Celeron G540 is 2.5GHz with 2MB of L3 cache. That's going to perform almost identically to the G620.

Actually, Intel is making a single core Celeron (to everyone's demise). It doesn't have HyperThreading, though. You save a whopping... wait for it... $5 dollars. So basically when it comes out the G530 will cost $50-55 and the G440 $45-50. You save $5 and you lose one entire core, and 1MB L3 cache.

/facepalm.jpg

AMD's pricing for the Athlon II X2 is just wrong, IMO. The Celeron G530 should be around the same speed and costs less, not to mention it'll consume a lot less power.

 

[Accord99]

HT does not give a 30% performance advantage. Many tests will tell you the same: it's 20%.

It's not always 20%, for the tests used by pconline, based on their 2600K/2500K review, we see that the 2600K, after accounting for the 3% clock advantage has a:

-25% advantage in Fritz
-38% advantage in wPrime
-22% advantage in Cinebench

http://diy.pconline.com.cn/cpu/reviews/1101/2331693_1.html

WinRAR 4.0's benchmark tool has the curious behavior of scaling exceptionally well with HT to 4 threads but scaling poorly beyond 4 threads, regardless of cores. From computerbase's review, the 2100T with HT enabled scores 59% higher KB/s.

http://www.computerbase.de/artikel/prozessoren/2011/test-intel-core-i3-2100t/19/

 

[LOL_Wut_Axel]

It's not always 20%, for the tests used by pconline, based on their 2600K/2500K review, we see that the 2600K, after accounting for the 3% clock advantage has a:

-25% advantage in Fritz
-38% advantage in wPrime
-22% advantage in Cinebench

http://diy.pconline.com.cn/cpu/reviews/1101/2331693_1.html

WinRAR 4.0's benchmark tool has the curious behavior of scaling exceptionally well with HT to 4 threads but scaling poorly beyond 4 threads, regardless of cores. From computerbase's review, the 2100T with HT enabled scores 59% higher KB/s.

http://www.computerbase.de/artikel/prozessoren/2011/test-intel-core-i3-2100t/19/

wPrime loves to inflate numbers higher than what they are, though. An example of that is how it puts 2 core/4 thread Atom as being basically the same speed as Core 2 Duo ULV, which is obviously absolute BS. Normally, as I said, it's 20%.

 

[Vesku]

Shame these are completely locked down, Sandybridge seems to have better thermal characteristics than the first gen i series. Could have been a nice flashback to the e2xxx days.

 

[NoobyDoo]

review : http://www.xbitlabs.com/articles/cpu/display/pentium-g850-g840-g620.html

 

[Zap]

review : http://www.xbitlabs.com/articles/cpu/display/pentium-g850-g840-g620.html

Thanks for the link! They listed the differences between these and the Core i3.

•Pentium doesn’t support Hyper-Threading technology that allows each computational core to execute two threads. Therefore, the operating system sees Pentium as a dual-core processor, unlike its elder brothers.
•Pentium graphics core doesn’t support Quick Sync technology. The owners of LGA1155 systems with these inexpensive processors inside won’t be able to take advantage of the integrated hardware unit that accelerated HD video playback.
•Pentium doesn’t support new vector and cryptographic instructions – AESNI and AVX.
•The memory controller in these processors works only with DDR3-1067/1333 SDRAM and doesn’t support higher memory frequency multipliers.
•The clock multiplier for the CPU frequency is dead locked. Pentium processors do not support Turbo Boost technology and do not overclock. Although this is also typical even of the higher-end Core i3 processors.

I knew it didn't support Turbo and Hyperthreading. Didn't know about the memory multipliers and Quick Sync. What the heck is "vector and cryptographic" and does it affect normal usage?

 

[pantsaregood]

review : http://www.xbitlabs.com/articles/cpu/display/pentium-g850-g840-g620.html

This basically shows how much my "60%-70% of i3-2100" performance estimate was a worst case scenario. The Pentiums are just trailing the 2100 by relatively small margins most of the time. The Athlon II X3 gets a chance to shine occasionally, too.

This also exemplifies the point that Celeron, as a branding, is going to completely fail to differentiate itself from Pentium. I still don't get it. Intel has releaed 1c/2t Celerons before.

 

[LOL_Wut_Axel]

This basically shows how much my "60%-70% of i3-2100" performance estimate was a worst case scenario. The Pentiums are just trailing the 2100 by relatively small margins most of the time. The Athlon II X3 gets a chance to shine occasionally, too.

This also exemplifies the point that Celeron, as a branding, is going to completely fail to differentiate itself from Pentium. I still don't get it. Intel has releaed 1c/2t Celerons before.

No, it was accurate. Again, the 2100 is much faster than the G620 in multi-threaded apps. I mean, really, who cares about single threaded apps anymore from a performance standpoint? Even most games from 2009 to now are decently multi-threaded (they take advantage of 3 cores) Who cares if a task like audio encoding that's 50 seconds on the G620 takes 45 seconds on the 2100? That's my main problem with single-threaded apps. They don't use many threads to begin with because they execute their instructions extremely quickly. That, in contrast to something like video encoding, which can take up a lot of time if the CPU doesn't have many resources.

Anyway, yes, Pentium is very much irrelevant. Celeron delivers a bit less performance, but at a much lower price. The G530 seems like an extremely good value proposition at ~$50. Intel may have just grabbed AMD by the balls in that market...

 

[pantsaregood]

You're right. Ideally, the i3 should definitely perform reasonably better than any of the Pentiums. Single-threaded applications aren't really a fault of the processor.

That said, the Pentiums being 60%-70% the speed of the i3 in multithreaded programs is very much a worst case scenario. HT is nice, but a 20% gain in performance isn't something that it always manages.

I don't know what to think of the Celerons/Pentiums. They're clearly Intel's attempt to shut down Llano. They have no hope of competing with Llano in games - Intel's GPUs are just too far behind. On the CPU side of things, SB Celerons/Pentiums are going to give AMD some trouble. $50 for a CPU/GPU that does everything the average PC user needs is going to be hard to compete with.

 

[VirtualLarry]

http://www.xbitlabs.com/articles/cpu/display/pentium-g850-g840-g620_7.html

Look at the power-consumption charts. SB is no more efficient than Core2!

Really nixes my plans for a low-power SB rig. Is power-gating of no use?

 

[pantsaregood]

http://www.xbitlabs.com/articles/cpu/display/pentium-g850-g840-g620_7.html

Look at the power-consumption charts. SB is no more efficient than Core2!

Really nixes my plans for a low-power SB rig. Is power-gating of no use?

Same use while idle. SB is more efficient under load. I would expect the low power Pentium to beat out a Core 2 by a decent margin.

 

[ydnas7]

http://www.xbitlabs.com/articles/cpu/display/pentium-g850-g840-g620_7.html

Look at the power-consumption charts. SB is no more efficient than Core2!

Really nixes my plans for a low-power SB rig. Is power-gating of no use?

did you bother to got to the next page
http://www.xbitlabs.com/articles/cpu/display/pentium-g850-g840-g620_8.html#sect0

 

[toyota]

http://www.xbitlabs.com/articles/cpu/display/pentium-g850-g840-g620_7.html

Look at the power-consumption charts. SB is no more efficient than Core2!

Really nixes my plans for a low-power SB rig. Is power-gating of no use?

its using less power than the only core 2 duo which is just an E7500. that's not bad considering that it is a faster cpu AND has graphics.

 

[bart1975]

I know I would have went with the Pentium G850 if it was available when I built my system. The problem is it takes Intel too long to put out something with a decent price in the low end range and when they do it is often too little to late.