The Sandy Bridge Pentium Review: G850, G840, G620 & G620T Tested
by Anand Lal Shimpi on August 23, 2011 12:11 AM ESTIn 2006 Intel introduced its tick-tock cadence for microprocessor releases. Every year would see the release of a new family of microprocessors as either a tick or a tock. Ticks would keep architectures relatively unchanged and focus on transitions to smaller manufacturing technologies, while tocks would keep fab process the same and revamp architecture. Sandy Bridge was the most recent tock, and arguably the biggest one since Intel started down this road.
At a high level the Sandy Bridge CPU architecture looked unchanged from prior iterations. Intel still put forth a 4-issue machine with a similar number of execution resources to prior designs. Looking a bit closer revealed that Intel completely redesigned the out-of-order execution engine in Sandy Bridge, while heavily modifying its front end. Sandy Bridge also introduced Intel's high performance ring bus, allowing access to L3 by all of the cores as well as Intel's new on-die GPU.
The Sandy Bridge GPU was particularly surprising. While it pales in comparison to the performance of the GPU in AMD's Llano, it does represent the first substantial effort by Intel in the GPU space. Alongside the integrated GPU was Intel's first hardware video transcoding engine: Quick Sync. In our initial review we found that Quick Sync was the best way to quickly transcode videos, beating out both AMD and NVIDIA GPU based implementations in our tests. Quick Sync adoption has been limited at best, which is unfortunate given how well the feature performed in our tests.
Sandy Bridge wasn't all rosy however. It was the first architecture that Intel shipped with overclocking disabled on certain parts. Any CPU without Turbo Boost enabled is effectively unoverclockable. Intel killed the low end overclocking market with Sandy Bridge.
The overclocking limits were a shame as Sandy Bridge spanned a wide range of price points. The low end Core i3-2100 was listed at $117 while the highest end Core i7-2600K came in at $317. While you can't claim that Sandy Bridge was overpriced at the high end, there's always room for improvement.
Despite abandoning Pentium as a high end brand with the 2006 release of Intel's Core 2 Duo, Intel has kept the label around for use on its value mainstream parts. Last year we saw only two Pentium branded Clarkdale parts: the G6950 and G6960. This year, powered by Sandy Bridge, the Pentium brand is a bit more active.
| Processor | Core Clock | Cores / Threads | L3 Cache | Max Turbo | Max Overclock Multiplier | TDP | Price |
| Intel Core i7 2600K | 3.4GHz | 4 / 8 | 8MB | 3.8GHz | 57x | 95W | $317 |
| Intel Core i7 2600 | 3.4GHz | 4 / 8 | 8MB | 3.8GHz | 42x | 95W | $294 |
| Intel Core i5 2500K | 3.3GHz | 4 / 4 | 6MB | 3.7GHz | 57x | 95W | $216 |
| Intel Core i5 2500 | 3.3GHz | 4 / 4 | 6MB | 3.7GHz | 41x | 95W | $205 |
| Intel Core i5 2400 | 3.1GHz | 4 / 4 | 6MB | 3.4GHz | 38x | 95W | $184 |
| Intel Core i5 2300 | 2.8GHz | 4 / 4 | 6MB | 3.1GHz | 34x | 95W | $177 |
| Intel Core i3 2120 | 3.3GHz | 2 / 4 | 3MB | N/A | N/A | 65W | $138 |
| Intel Core i3 2100 | 2.93GHz | 2 / 4 | 3MB | N/A | N/A | 65W | $117 |
| Intel Pentium G850 | 2.9GHz | 2 / 2 | 3MB | N/A | N/A | 65W | $86 |
| Intel Pentium G840 | 2.8GHz | 2 / 2 | 3MB | N/A | N/A | 65W | $75 |
| Intel Pentium G620 | 2.6GHz | 2 / 2 | 3MB | N/A | N/A | 65W | $64 |
| Intel Pentium G620T | 2.2GHz | 2 / 2 | 3MB | N/A | N/A | 35W | $70 |
The new Sandy Bridge based Pentiums fall into two lines at present: the G800 and G600. All SNB Pentiums have two cores (HT disabled) with 256KB L2 per core and a 3MB L3 cache. CPU core turbo is disabled across the entire Pentium line. From a performance standpoint, other than missing hyper threading and lower clocks - the Sandy Bridge Pentiums are very similar to Intel's Core i3.
Intel continues to separate the low end from the high end by limiting supported instructions. None of the Pentiums support AES-NI or VT-d. Other than higher clock speeds the 800 series only adds official DDR3-1333 support. The 600 series only officially supports up to DDR3-1066.
All standard Pentiums carry a 65W TDP. The Pentium G620T runs at a meager 2.2GHz and manages a 35W TDP. Regardless of thermal rating, the boxed SNB Pentiums come with an ultra low profile cooler:
These Pentium CPUs work in the same 6-series LGA-1155 motherboards as their Core i3/5/7 counterparts. The same rules apply here as well. If you want video out from the on-die GPU you need either an H-series or a Z-series chipset.
The Pentium GPU
When Intel moved its integrated graphics on-package with Clarkdale it dropped the GMA moniker and started calling it HD Graphics. When it introduced the Sandy Bridge Core i3/5/7, Intel added the 2000 and 3000 suffixes to the HD Graphics brand. With the Sandy Bridge Pentium, Intel has gone back to calling its on-die GPU "HD Graphics".
Despite the name, the Pentium's HD Graphics has nothing in common with Clarkdale's GPU. The GPU is still on-die and it features the same architecture as Intel's HD Graphics 2000 (6 EUs). Performance should be pretty similar as it even shares the same clock speeds as the HD 2000 (850MHz base, 1.1GHz turbo for most models). I ran a quick test to confirm that what Intel is selling as HD Graphics is really no different than the HD Graphics 2000 in 3D performance:
All is well in the world.
Where the vanilla HD Graphics loses is in video features: Quick Sync, InTru 3D (Blu-ray 3D), Intel Insider (DRM support for web streaming of high bitrate HD video) and Clear Video HD (GPU accelerated post processing) are all gone. Thankfully you do still get hardware H.264 video acceleration and fully audio bitstreaming support (including TrueHD/DTS-HD MA).
Missing Quick Sync is a major blow, although as I mentioned earlier I'm very disappointed in the poor support for the feature outside of the initial launch applications. The rest of the features vary in importance. To someone building a basic HTPC, a Sandy Bridge Pentium will do just fine. Personally I never play anything in 3D, never use the Clear Video HD features and never use Intel Insider so I wouldn't notice the difference between a Sandy Bridge Pentium and a Core i5 for video playback.
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Taft12 - Tuesday, August 23, 2011 - link
People who visit AT are the last holdouts of the desktop PC generation.philosofool - Wednesday, August 24, 2011 - link
Businesses and schools. Or, about half the market for computers.alent1234 - Tuesday, August 23, 2011 - link
last year i bought a $299 laptop as a gift for someone. it's more than enough for that person.i actually wanted to buy them an ipad but my wife said laptop
Yowen - Monday, August 29, 2011 - link
Yeah, for personal use that's fine, but I'd love to run it for the hours that I run my desktop at work and see how long it lasts. So there is still a very sizable market for desktops.averik - Tuesday, August 23, 2011 - link
I don't think so. We recently bought 24 G620 Pentiums to replace socket 478 Pentium 4s in 2 highschools.The CPU market for doing "basic staff" is quite large, and its impressive that G620 is almost as powerful as the Core 2 E8500 which had a release price of $266.
philosofool - Wednesday, August 24, 2011 - link
Exactly.This review is naturally targeted at the single user building his own system.
If you're a public library or a high school or a medium sized office looking to upgrade 20 computers that are running 9am to 9pm daily, a 35W pentium destroys the competition. A 100W anything is a waste of money because the extra 1300W power consumption bites would cost you quite a lot of money in electricity. The power company charges a lot more when you're consuming a lot of power (like a business) than when you're consuming a little (like a home.)
yankeeDDL - Thursday, August 25, 2011 - link
Guys, please, let't be serious.You cannot possibly do considerations on power consumption by looking at a chart showing the power under load, do you?
If you do, then you should have bought Atoms: at 9W they're for sure much better than any Athlon and G*.
So why didn't you buy an Atom instead? Exactly, because it's slow.
What good does it make to use less power, if it takes you longer to do the same thing?
The G620, under load, consumes about 55% of the Athlon X3, but the Athlon takes 60% of the time that the G620 takes to do the same task (I'm looking at the x264 charts). So the difference between these two, under load, is anecdotal, at best.
So, I'm sorry for your highschools, but you did not save them much money in electricity. Infact, considering how more expensive the MoBos for SB are, you probably ended up making them pay more.
averik - Monday, August 29, 2011 - link
Cost of Athlon X3 + cheap Asus mboard = Cost of G620 + cheap Asus H61 mboard (about 125 Euros).Athlon X3 is a great CPU and in fact I use one at work. But most of the time CPUs are idle. We dont do any x264 work. In fact, i believe the typical hardest daily job of a CPU is to startup windows, antivirus etc.
In the low badget market you cannot go awfully wrong, so even Athlon X2 is a good choice, but AMDs line is aged. Pentium G*s on the other hand offer comperable performance at same price on a newer platform.
yankeeDDL - Friday, September 2, 2011 - link
Averik,respectfully, I disagree.
From Newegg: Biostar N68S = $40, Ath II X3 440 = $65
Biostar H61ML = $50 G620 = $75
Delta: $20 (out of $105, it's ~20%).
Note: the MoBos are the cheapest I found. The one for AMD also has onboard Video, saving you a few extra bucks if you don't do gaming.
If you are an extremely "light" user (email + web browsing), then neither the G620 or the Athlon X3 make much sense: Brazos (either the E-350 or the C-50) make a lot more sense, since their power consumption is abismal compared to the other two, and they pack plenty of speed for those tasks. Plus, the on-chip GPU accelerates web content nicely.
If you add to the mix some casual gaming, Brazos can even handle it, but it won't compare with either the Athlon of the G620. If you trust Tom's hardware, you can see that they recommend the X3 easily, because of the 3rd core, which helps in several scenario, despite the lower efficiency over the 2 cores of the G620.
I can imagine only some very, very specific scenarios (very limited budget, low PSU capacity, occasional gaming, lots of encryption) where the G620 has a slight edge over the X3, but that's far from average Joe budget PC.
You're totally right about not going "awfully" wrong with the G620, nevertheless, you do pay the "Intel" brand price over a slightly less performing CPU.
You're also right about AMD line being aged, but again, if you are looking at G620, you are looking into budget-oriented systems: not something you change every other day, so what is wrong wit being aged? In my view, you can find tons of good combo deals, and maybe even used parts, which could dramatically drop your costs.
Also, Intel isn't exactly famous for keeping things compatible: it wouldn't be the 1st time that the socket gets quickly outdated (was it really necessary to have a socket 1156 and an 1155?), while AMD's socket gets you covered up to the Phenom II X4, for a dirt-cheap bump in performance.
That's the way I see it at least. I would love to see the prices of the G620 going below $50: that would be a real deal (and I'm sure would push AMD's prices even lower). Till that happens, for budget, I buy AMD, which gives the best bangs for the bucks.
averik - Sunday, September 4, 2011 - link
yankeeDDL, I agree with many of your points (especially changing sockets). Please note however that best prices or used items are not an option for some buyers.The scenario is extremely light use (email, web browsing, ms office, thin-client intranet applications, light educational applications), but the investment has to last for 5-10 years (we are replacing P4s - I know its a shame). I am not sure how heavily threaded the environment will be in then. If it is, then yes, Athlon X3 will perform a bit better. If not, then G620 having better single-thread performance will be better. Both will be old though.
I also found the case of E350 very interesting - to replace bulkier equipment with ITX motherboards and small cases - so I built one for home and use it daily. My conclusion is something like Brazos will be a good mid-term investment for basic office use if (1) they get 50% better CPU power (graphics are ok) and (2) availability of PSUs for ITX cases gets better - I mean it should be as trivial to find a replacement as a regular PSU is. But sure, thats the way of things to come.
As for G620 going below $50, I dont have high hopes. Maybe the cheapest Bulldozers (when they appear) will force Intel to do that - but why go for G620 then?
I really liked reading your comments.