In 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.

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.

The Matchup

The Sandy Bridge Pentiums go head to head with AMD's Athlon II and to a lesser extent the new triple-core AMD A6. At the low end we have the Athlon II X2 260 vs. Intel's Pentium G620. AMD has the clock speed advantage (3.2GHz vs. 2.6GHz) but Sandy Bridge does offer better performance at the same clock, we'll have to see if the 600MHz advantage is too much for Intel to overcome.

Moving on up AMD gets to throw more cores at the competition. The Athlon II X3 455 (3.3GHz) has three cores to the Pentium G840's two (2.8GHz), although the clock speed advantage shrinks a bit.

Finally compared to the Pentium G850 we have two options from AMD. If you can find one there's the Athlon II X4 635. The clock speed advantage goes away completely but AMD delivers twice the cores of Intel's Pentium G850. The 635 is no longer on AMD's price list so your chances of finding one at a reasonable price go down considerably. The Athlon II X3 460 is the only other similarly priced competitor, and its performance should be similar to the 455 I mentioned above.

Meet the A6

Although at a slightly higher price point than the most expensive Sandy Bridge Pentium, we also have a lower cost member of the Llano family: AMD's A6-3650. For $20 less than the flagship 3850, the A6-3650 loses 300MHz on the CPU clock and lops off 80 GPU cores. The GPU also runs at a slower 443MHz frequency. The TDP remains unchanged at 100W. Given the small price difference between a 3650 and a 3850 I'd much rather opt for the latter but we'll see what the slower GPU does to performance when every dollar counts.

The Test

As always we're only presenting a subset of our entire CPU test suite here. For all of the numbers as well as other comparison options check out Bench.

Adobe Photoshop CS4 Performance

To measure performance under Photoshop CS4 we turn to the Retouch Artists’ Speed Test. The test does basic photo editing; there are a couple of color space conversions, many layer creations, color curve adjustment, image and canvas size adjustment, unsharp mask, and finally a gaussian blur performed on the entire image.

The whole process is timed and thanks to the use of Intel's X25-M SSD as our test bed hard drive, performance is far more predictable than back when we used to test on mechanical disks.

Time is reported in seconds and the lower numbers mean better performance. The test is multithreaded and can hit all four cores in a quad-core machine.

The Pentium G620 does a lot better than its Athlon II X2 counterpart, there's no contest here. The race is a lot closer between the G840/850 and the Athlon II X3 455, but in the end the Pentiums are faster. Both perform a bit better than the more expensive AMD A8-3850.

x264 HD Video Encoding Performance

Graysky's x264 HD test uses the publicly available x264 encoder to transcode a 4Mbps 720p MPEG-2 source. The focus here is on quality rather than speed, thus the benchmark uses a 2-pass encode and reports the average frame rate in each pass.

Once again the G620 is faster than the Athlon II X2 265 despite the latter's clock speed advantage. The G840 and G850 are faster than the 620 but not fast enough to overcome the extra core advantage of the X3 455. If you're spending $80 on a CPU for video encoding go for the Athlon II X3 455.

3dsmax 9 - SPECapc 3dsmax CPU Rendering Test

Today's desktop processors are more than fast enough to do professional level 3D rendering at home. To look at performance under 3dsmax we ran the SPECapc 3dsmax 8 benchmark (only the CPU rendering tests) under 3dsmax 9 SP1. The results reported are the rendering composite scores:

Not all heavily threaded tasks are going to favor more cores. In this case the IPC advantages of Sandy Bridge give the G850 equal performance to the X3 455.

Cinebench R10

Created by the Cinema 4D folks we have Cinebench, a popular 3D rendering benchmark that gives us both single and multi-threaded 3D rendering results.

Single threaded performance is going to be a big advantage of the SNB Pentiums. Even the G620 is a good 14% faster than AMD's Athlon II X2 265 and the rest scale up with clock speed. What this translates to is great general use performance as well as solid performance in those apps that are still bound by the performance of a single thread.

Multithreaded apps however start to benefit from more cores. In this case the Athlon II X3 455 isn't much faster than a G850 and only 4.5% faster than a G840, despite its core count advantage.

PAR2 Multithreaded Archive Recovery Performance

Par2 is an application used for reconstructing downloaded archives. It can generate parity data from a given archive and later use it to recover the archive

Chuchusoft took the source code of par2cmdline 0.4 and parallelized it using Intel’s Threading Building Blocks 2.1. The result is a version of par2cmdline that can spawn multiple threads to repair par2 archives. For this test we took a 708MB archive, corrupted nearly 60MB of it, and used the multithreaded par2cmdline to recover it. The scores reported are the repair and recover time in seconds.

Our Par2 extraction test is another multithreaded scenario where two Sandy Bridge cores manage to slightly outperform three Athlon II cores. Whereas before it was a pretty simple "more cores, better multithreaded performance" argument, the SNB Pentiums do complicate things a bit.

WinRAR - Archive Creation

Our WinRAR test simply takes 300MB of files and compresses them into a single RAR archive using the application's default settings. We're not doing anything exotic here, just looking at the impact of CPU performance on creating an archive:

Once again we've got a multithreaded test with a murky outcome. The G850 is hot on the heels of the Athlon II X3 455, as is the G840.

Gaming Performance

Our first set of gaming performance results come using a discrete GPU. In the case of the Crysis Warhead results it's a GeForce GTX 280, while everything else uses a Radeon HD 5870. Across the board the Pentium manages to do better than its Athlon II competitors, of course with a discrete GPU that's not unexpected. Next we'll see how these stack up with processor graphics.

Dragon Age Origins is another very well received game. The 3rd person RPG gives our CPUs a different sort of workload to enjoy:

World of Warcraft needs no introduction. An absurd number of people play it, so we're here to benchmark it. Our test favors repeatability over real world frame rates, so our results here will be higher than in the real world with lots of server load. But what our results will tell you is what the best CPU is to get for playing WoW:

Power Consumption

The new Pentiums draw very little power, not only compared to their AMD counterparts but also the rest of the Sandy Bridge lineup.Without Hyper Threading, overall execution resource utilization is lower and thus power consumption is lower. It doesn't look like any of these chips come close to hitting their max TDPs as the Pentium G620T only draws 4W less than the G620 despite being rated with a 30W lower TDP.

Processor Graphics Performance

The Sandy Bridge Pentium lineup features the performance equivalent of Intel's HD Graphics 2000. AMD's A6-3650 on the other hand sports a 320 core GPU called the Radeon HD 6530D. How do the two stack up? What about compared to the A8-3850's Radeon HD 6550D? We're about to find out.

We'll start with the A6-3650 vs. the Pentium G850. I didn't include the slower Pentiums because there's simply no point to. The A6-3650's Radeon HD 6530D GPU is on average 2.33x the speed of the Pentium G850 across all of our tests and all resolutions. There's simply no competition and at these frame rates, even at 1024 x 768, I wouldn't consider the G850's graphics playable unless you go to older games or really make the game look terrible.

AMD A6 vs. AMD A8

What about the AMD A6 vs. A8? On average the A8's higher GPU clock and 80 extra GPU cores give it an 18 - 26% performance advantage over the A6's GPU depending on resolution. Both systems here use DDR3-1600 memory and despite memory bandwidth being constrained across the board, the A8's advantage increases with resolution.

The Processor Graphics Gaming Charts

How do these on-die GPUs compare to discrete offerings? This page has the data I presented on the previous one but in a comparison format to discrete GPUs:

Final Words

Despite boasting Intel's latest Sandy Bridge microarchitecture, the conclusions here are pretty much unchanged from the past. Intel maintains an advantage when it goes up against an AMD chip with the same number of cores, almost regardless of clock speed. In the case of the Pentium G620, even an Athlon II X2 265 with a 27% clock speed advantage can't outperform the Sandy Bridge based CPU. If you're choosing between chips with the same number of cores at the same price, Intel wins.

The decision tilts in AMD's favor if you start comparing to the Athlon II X3. In heavily threaded workloads, the Athlon II X3's third core helps put it ahead of the entire SNB Pentium lineup. If you're building a machine to do offline 3D rendering, multithreaded compiling or video transcoding then AMD continues to deliver the best performance per dollar. It's in the lighter, less threaded workloads that the Pentium pulls ahead. If you're building more of a general use system (email, web browsing, typical office applications and even discrete GPU gaming), the Pentium will likely deliver better performance thanks to its ILP advantages. What AMD has offered these past couple of years is an affordable way to get great multithreaded performance for those applications that need it.

Unfortunately the entire Sandy Bridge Pentium lineup is clock locked. Without turbo modes there's no support for overclocking at all. While these new Pentiums would have normally been great for enthusiasts looking to overclock, Intel has ensured that anyone looking to get more performance for free at the low end will have to shop AMD. Unfortunately Intel's advantage in single/lightly threaded performance is big enough that a clock speed advantage alone is generally not enough to make up for it (see G620 vs. Athlon II X2 265 comparison). It's sad that it has come to this. I was hoping we'd see more K-series SKUs at the low end but it seems like those will only be for the enthusiasts at the high end.

The Pentium's on-die GPU isn't particularly impressive. It's the HD Graphics 2000 from the rest of the Sandy Bridge lineup without Quick Sync or any of the extra video features. I am particularly sad that Quick Sync is missing as it would've made these Pentiums extremely attractive for users that do a lot of video transcoding. Thankfully video decode acceleration and HD audio bitstreaming support remain, so if you're looking to build a cheap Sandy Bridge based HTPC and don't care about the frills these chips will work just fine.

However, if you're building a system to do any sort of 3D gaming you're much better off either springing for a cheap discrete card or looking at AMD's A6-3650 if you want to stay integrated. Although you can play older titles at low resolution on the Pentium's on-board GPU, you'll have a much better experience with a discrete GPU or with the A6.

It all boils down to this. If you want a good, cheap, general purpose PC then the Pentium G620 seems competent and cheap. You can consider the G840 if you want a bit more performance. If you do a lot of threaded work (e.g. offline 3D rendering) the next step up is the Athlon II X3 455. If you do any amount of consumer level video transcoding using apps that are Quick Sync enabled, opt for the Core i3 2100 instead. If gaming is important to you then either buy a discrete GPU or look to AMD's Llano.

As far as AMD's A6 vs. A8 goes, the A8-3850 only commands a $20 price premium over the A6-3650. That $20 gives you another 8 - 10% on the CPU side and around 20% on the GPU. In my opinion, if you're considering a Llano system - spring for the A8.