Oh man. Oh man oh man. So, yes, the desktop processor market has been kind of a sleepy place of late. The story has been Intel’s consistent dominance, AMD’s repeated struggles, and not much in the way of performance progress. Worse still, prices have stagnated for way, way too long. There’s been precious little reason to consider an upgrade. Happily, Intel has decided to inject a little excitement into things by releasing a really cheap CPU that’s completely unlocked, the Pentium G3258. I’d say they’ve nailed it: excitement achieved.

This new Pentium is an unlocked dual-core CPU based on the latest 22-nm Haswell silicon. The list price is only 72 bucks, but Micro Center had them on sale for $60. In other words, you can get a processor that will quite possibly run at clock speeds north of 4GHz—with all the per-clock throughput of Intel’s very latest CPU core—for the price of a new Call of Shooty game. I ran out and picked one up as soon as they went on sale last week. Almost seems too good to be true. But is it? Let’s have a look at how this one performs.

A 20th anniversary gift

The Pentium G3258 is an Anniversary Edition, meant to “celebrate” 20 years of the Pentium brand. Because we live in the future, it delivers way more than 20 times the performance of the original Pentium 100. The G3258’s stock clock is 3.2GHz, or 32X that of the Pentium 100. And it has dual cores, so count it at 64X. Then multiply by some amount of increased per-clock instruction throughput and sprinkle in some gains from vector math and such. Don’t forget the vast increases in cache and memory performance, either. You’re surely at 128X the peak performance of a Pentium 100 at the end of the day, by my horrible, back-of-the-napkin estimation. Perhaps much more.

I dunno what that means, really. As a writer, though, I’m obligated to throw some big numbers at you as part of any retrospective involving the magic of Moore’s Law.

Oddly enough, the Pentium G3258 is kind of a weakling at its stock speeds. Pentium is now a “value” brand, and Intel has hobbled its low-end processors in various ways in order to keep its higher-end CPUs looking attractive. Intel has disabled a bunch of features, including Hyper-Threading, VT-d, TSX, vPro, AES-NI, and TXT. The spec sheet is like an alphabet soup of “nope.” Also, this chip has a relatively skimpy 3MB L3 cache, and its supported memory speeds top out at 1333 MT/s.

Thing is, in my view, that list of gimped specs is also a cavalcade of “don’t care.” Take the cache size, for instance. The working data set for most desktop programs is surely way less than 3MB. Larger caches are mostly helpful for sharing data between multiple cores—and with only two cores, the G3258 has less need for cache in that role. At the same time, Intel hasn’t lobotomized the QuickSync video transcoding block in this little Pentium. Video encoding is one of those few common desktop tasks where four cores is a big win, but the presence of dedicated hardware eases that worry.

More importantly, where we’re going, stock speeds don’t matter, and an abundance of hertz can make up for a whole host of other missing features. Overclocking this thing is a simple matter of twiddling a few bits in a BIOS menu.

Punch it, Chewie.

I strapped the Pentium G3258 into my Haswell test rig, which includes an Asus Z97-A motherboard and a Thermaltake NiC C5 cooler. The cooler’s specs say it can dissipate up to 230W, so I figured it should have plenty of headroom for this CPU with a 53W stock TDP.

I took the same basic approach to overclocking the G3258 that I took with Devil’s Canyon, making tweaks to the CPU multiplier and voltage in the motherboard’s firmware and leaving most other settings at “Auto.” Asus’ firmware tends to ramp up some secondary voltages automagically to improve stability while you’re overclocking, and I let it do so.

This Pentium came out of the box running at 3.2GHz and 1.04V. I fired up Prime95 to use as a load test. The Asus AISuite utility reported CPU power draw under load at just 30.8W, way less than the CPU’s max rating. Core temperatures were steady at 29°C. So yeah, early indications were good.

After just a few attempts, this G3258 was up and running stable at 4.8GHz and 1.375V. I tried for more, of course. The G3258 booted into Windows at 4.9GHz, but the blue screen of death came to visit once I ran Prime95. I tried cranking up the voltage to 1.4V and then 1.425V, but the extra juice didn’t help. 4.8GHz looked to be the practical limit.

Which is, you know, really quite nice. Our Core i7-4790K topped out at 4.7GHz and required more voltage to get there. Heck, since the Pentium’s stock clock is just 3.2GHz, this amounts to a 50% overclock. That’s a magical number us old farts associate with the ur-overclocker, ye olde Celeron 300A.

At this speed, the G3258’s temperatures rose to around 64°C under load, and AISuite estimated CPU power draw at 64.5W—not that I entirely trust that number. I stuck the test system on a power meter, and the whole thing draws 119W at the wall socket with Prime95 cranking. That’s not bad at all. I was able to dial back the NiC C5’s fan speed to about 1100 RPM, where it emits just a whisper of noise, and still keep the CPU’s core temperatures in the mid-60s.

Just for good measure, I also kicked up the memory speed to 1600 MT/s, which presented no problem at all for the G3258.

The Athlon X4 750K edges in on the action

AMD may not be competing too vigorously against Intel’s high-end CPUs these days, but when you get into budget territory—and especially unlocked CPUs with lots of bang for the buck—then you’ve just stepped into AMD’s wheelhouse. AMD’s current answer to the Anniversary Edition Pentium is the Athlon X4 750K, an unlocked quad-core processor selling for $79.99 at Newegg. AMD was kind enough to provide us with one to test against the Pentium G3258.

The X4 750K is based on Trinity silicon, which means it’s a generation or two behind the latest Kaveri chips, depending on how you’re counting. Still, the 750K’s dual “Piledriver” modules are pretty well suited for this mission. With four integer cores, two FPUs, dual 2MB L2 caches, a 3.7GHz base clock, and a 4GHz Turbo peak, the Athlon X4 brings somewhat beefier hardware to this fight than the Pentium does. The Athlon X4 officially supports DDR3 memory speeds up to 1866 MT/s, too.

In keeping with its general M.O., AMD has left this chip’s special features largely intact, so instructions like AES-NI for accelerated encryption are fully available. That’s nice. The one exception is built-in graphics. The Radeon IGP has been disabled in the Athlon X4—not that we’re likely to miss it with a discrete graphics card installed.

Even without the Radeon IGP, AMD is clearly willing to give you more hardware for your money at this price. There’s a trade-off, though, as with most AMD CPU offerings these days. The X4 750K’s default TDP rating is 100W—nearly double that of the Pentium G3258. That’s the starting point, and the 750K will likely draw even more power once it’s overclocked.

To test the X4 750K’s potential, I dropped it into an Asus A88X-Pro motherboard and attached a massive Cooler Master tower.

With a little tweaking, the 750K was soon running reliably at 4.5GHz and 1.425V.

I tried pushing as high as 1.525V in an attempt to get it stable at 4.6GHz, but that wasn’t meant to be. Consistently, one particular thread in our Prime95 test would exit with a computational error. One of the four cores evidently wasn’t happy at higher clocks. 4.5GHz isn’t bad, but it’s a little less than the 4.8GHz we reached with the Richland-derived A10-6800K. Ah, well.

I used the AMD Overdrive utility to monitor the CPU’s state while overclocking. This utility doesn’t report absolute CPU temperatures, but it said there was still 32°C worth of “margin,” or headroom, in the overclocked 750K when running Prime95. The entire Athlon X4 750K test rig pulled 163W at the wall socket during this same workload.

AMD’s Piledriver can’t match Intel’s Haswell clock for clock, but at 4.5GHz, the Athlon X4 750K ought to give the Pentium G3258 a run for its money in multithreaded tests. Right? Let’s have a look.

Our testing methods

The test systems were configured like so:

Processor AMD FX-8350 AMD A10-7850K Athlon X4

750K Motherboard Asus Crosshair V Formula Asus A88X-PRO Asus A88X-PRO North bridge 990FX A88X FCH A88X FCH South bridge SB950 Memory size 16 GB (2 DIMMs) 16 GB (4 DIMMs) 16 GB (4 DIMMs) Memory type AMD Performance Series DDR3 SDRAM AMD Radeon Memory Gamer Series DDR3 SDRAM AMD Radeon Memory Gamer Series DDR3 SDRAM Memory speed 1600 MT/s 2133 MT/s 1866 MT/s Memory timings 9-9-9-24 1T 10-11-11-30 1T 10-11-11-30 1T Chipset drivers AMD chipset 13.12 AMD chipset 13.12 AMD chipset 13.12 Audio Integrated SB950/ALC889 with Realtek 6.0.1.7233 drivers Integrated A85/ALC892 with Realtek 6.0.1.7233 drivers Integrated A85/ALC892 with Realtek 6.0.1.7233 drivers OpenCL ICD AMD APP 1526.3 AMD APP 1526.3 AMD APP 1526.3 IGP drivers – – –

Processor Core i5-2500K Core i7-3770K Core

i7-4770K Core i7-4790K Pentium

G3258 Motherboard Asus P8Z77-V Pro Asus P8Z77-V Pro Asus Z97-A Asus Z97-A North bridge Z77 Express Z77 Express Z97 Express Z97 Express South bridge Memory size 16 GB (2 DIMMs) 16 GB (2 DIMMs) 16 GB (2 DIMMs) 16 GB (2 DIMMs) Memory type Corsair Vengeance Pro DDR3 SDRAM Corsair Vengeance Pro DDR3 SDRAM Corsair Vengeance Pro DDR3 SDRAM Corsair Vengeance Pro DDR3 SDRAM Memory speed 1333 MT/s 1600 MT/s 1600 MT/s 1333 MT/s Memory timings 8-8-8-20 1T 9-9-9-24 1T 9-9-9-24 1T 8-8-8-20 1T Chipset drivers INF update 10.0.14 iRST 13.0.3.1001 INF update 10.0.14 iRST 13.0.3.1001 INF update 10.0.14 iRST 13.0.3.1001 INF update 10.0.14 iRST 13.0.3.1001 Audio Integrated Z77/ALC892 with Realtek 6.0.1.7233 drivers Integrated Z77/ALC892 with Realtek 6.0.1.7233 drivers Integrated Z97/ALC892 with Realtek 6.0.1.7233 drivers Integrated Z97/ALC892 with Realtek 6.0.1.7233 drivers OpenCL ICD AMD APP 1526.3 AMD APP 1526.3 AMD APP 1526.3 AMD APP 1526.3

They all shared the following common elements:

Hard drive Kingston HyperX SH103S3 240GB SSD Discrete graphics XFX Radeon HD 7950 Double Dissipation 3GB with Catalyst 14.6 beta drivers OS Windows 8.1 Pro Power supply Corsair AX650

Thanks to Corsair, XFX, Kingston, MSI, Asus, Gigabyte, Intel, and AMD for helping to outfit our test rigs with some of the finest hardware available. Thanks to Intel and AMD for providing the processors, as well, of course.

Some further notes on our testing methods:

The test systems’ Windows desktops were set at 1920×1080 in 32-bit color. Vertical refresh sync (vsync) was disabled in the graphics driver control panel.

The tests and methods we employ are usually publicly available and reproducible. If you have questions about our methods, hit our forums to talk with us about them.

Rendering and video encoding

Welp, this first result gives us a sense of how this story is about to unfold. When clocked at 4.8GHz, the Pentium G3258 is among the fastest CPUs you can buy in terms of single-threaded performance. Only the overclocked Core i7-4790K outperforms it, perhaps due to the 4790K’s larger 8MB L3 cache. Even when overclocked to 4.5GHz, the Athlon X4 750K can’t match the single-threaded performance of the stock-clocked Pentium. Jeez.

The contest grows closer when multiple threads are involved, but the overclocked Pentium still outperforms the overclocked Athlon slightly.

x264 encoding doesn’t scale as perfectly with multiple threads as Cinebench does, and it relies solely on the CPU cores, so QuickSync and other hardware encoders don’t get involved. Impressively, the overclocked G3258 darn near keeps pace with the eight-core FX-8350, one of AMD’s fastest desktop processors. The Pentium’s two cores at 4.8GHz also put it within reach of an enthusiast stalwart, the Core i5-2500K, a quad-core Sandy Bridge. This is crazy-fast performance for a $60 processor. Or $72. Whatever.

But how does a fast dual-core CPU perform in a modern game engine? Hmm.

Crysis 3





As usual, we’ve recorded every frame of animation in our gaming tests and are reporting results based on the entire distribution of frame times. This method lets us look much deeper than a simple FPS average would—and it reveals some interesting things about the performance of our overclocked Pentium. Click through the buttons above to see plots of the frame times from one of our three test runs for each CPU. Pay special attention to the overclocked G3258.

In this case, the FPS average and our frame-time-focused 99th percentile metric agree: the dual-core Pentium at 4.8GHz handles our Crysis 3 test scenario pretty nicely overall, jockeying for position versus the FX-8350 and the Core i5-2500K.

What’s intriguing is how the overclocked Pentium manages this feat. Crysis 3 clearly takes advantage of four or more hardware threads when they’re available; look at how poorly the Pentium fares at stock speeds compared to the Athlon X4 and friends. Still, the G3258 more than makes up the deficit at 4.8GHz, thanks to good, old-fashioned per-core performance. Suddenly, it’s in the mix with much higher-end CPUs.

Now, check out what happens when we look closely at the hiccups, those frames of animation where the game runs slowest on each system.





Per-thread performance matters tremendously in avoiding the slowdowns that interrupt smooth gaming. The Pentium G3258 at 4.8GHz looks pretty good at our 99th percentile cutoff, but it gets even stronger during the last, most difficult 1% of frames rendered. There, it outperforms the stock-clocked Core i5-2500K and i7-4770K, and it handily outdoes any AMD CPU you can buy.





The benefits of the G3258’s killer per-thread performance are best illustrated by our “badness” metric, which looks at the time spent working on frames above a series of thresholds. The more time spent working on frames that take longer than, say, 33 milliseconds (or two display refresh intervals at 60Hz) to produce, the slower the game is likely to feel.

Conclusions

Take a second to consider what those Crysis 3 results mean. At 4.8GHz, the Pentium G3258 avoids slowdowns much more capably than even AMD’s FX-8350. Just like car guys say “there’s no replacement for displacement,” we’ve gotta admit that there’s no replacement for per-thread performance. In a great many cases, including games, the user experience relies mostly on one single, gnarly thread’s execution. With only two cores and two hardware threads at its disposal, the overclocked Pentium G3258 can still feel very snappy thanks to its combination of unusually high revs and prodigious instruction throughput in each clock cycle.

We need to do more testing, but an overclocked G3258 looks to be a truly outstanding gaming CPU—not only on a budget, but just generally compared to much more expensive CPUs.

With that said, it’s time to pile on the caveats. For one thing, we can’t assume that every Pentium G3258 will reach 4.8GHz at under 1.4V like ours did. Happily, the early reports so far from end users do seem pretty promising, with speeds in excess of 4GHz looking common.

Beyond that, like I said, we need to do more testing. A fast dual-core, two-threaded CPU isn’t terribly common these days, and I’m curious how it performs across a range of newer games and other applications. Fortunately, I’m in a position to do something about that. We’ve already started compiling a pretty good set of results. I’ll see what we can do about adding more tests soon.

Also, although the Pentium G3258 kind of left the Athlon X4 750K in the dust in our first round of tests, AMD has newer silicon it could choose to position against the Pentium Anniversary Edition. I wouldn’t be surprised to see a more potent response from AMD in the coming weeks.