ASUS GTX 670 DirectCU Mini Graphics Card Review

We review a lot of powerful video cards here. Between three of our editors, we have three GTX 780 being put through their paces. However, you can’t always fit that kind of power in the system you want to build. What if you’re into small form factor (SFF) computer building? There is an entire community of SFF builders in our own forums. Gamers that enjoy going to LAN parties also run into issues not wanting to lug around fifty plus pound rigs around. ASUS thinks they have their answer for you – the ASUS GTX 670 DirectCU Mini.

Specifications & Features

The GTX 670 DirectCU Mini is a full fledged GTX 670 with a slightly higher than reference base / boost clock of 928 MHz / 1006 MHz (reference is 915 MHz / 980 MHz). There is a 2 GB frame buffer operating at 1502 MHz (6008 MHz GDDR5 quad-pumped).

Its size is its main selling point but ASUS hasn’t cut any corners; just shrunk it.

The DirectCU Mini is only 17 cm long, 29.5% shorter than the reference card.

When compared to the reference card, ASUS’ numbers show anywhere from 4.9 ~ 8.7% improvement over reference. Note these graphs don’t start at zero, so pay no attention to the giant PR bars (ZOMG it’s so much better!).

The GTX 670 DirectCU Mini doesn’t stick and hold a boost clock throughout benches. With GPU Boost 1.0, it’s dependent on the available power target. Because of that spike in 3DMark 11 for the combined test, I used HWBot Heaven Xtreme to average the boost clock throughout the run. The average ended up at a strong 1073.8 MHz.

Enough specs talk, time to get to the card.

Meet the ASUS GTX 670 DirectCU Mini

Oh em gee, a monster clawed the box! (Again…like all of ASUS’ GPU boxes). As usual, the card is well packed and safe for travel.

Accessories are slim but admittedly there isn’t much you need with this – or any – GPU. You get a speed setup guide, driver disc and a dual 6-pin to single 8-pin power adapter.

The card itself is very nice looking. So short, it’s nearly square, they did a good job making it not look boring.

Power is supplied by a single 8-pin PCIe connector. As you can see, the shroud is opened up all around to allow air to escape the small heatsink from all sides. If you go with this card, make note of that and ensure you have adequate case airflow. In a large case that is usually a small concern, but in a SFF case with a lot of components crammed into a tiny space, things can heat up quickly.

The video outputs are the same as reference – two DVI, one HDMI and one full size DisplayPort.

For a small card, it looks pretty good from this reviewer’s perspective. Let’s take it apart.

Under the Hood

Pulling the heatsink off, the first thing you’ll probably notice is that there is contact with all of the GPU-side vRAM and all MOSFETs as well as the GPU. So from the start, you can tell this is a smartly designed heatsink.

ASUS kindly blew up the heatsink for our viewing pleasure. This isn’t your standard heatsink; a fair bit of engineering went into making this thing strong. There is a vapor chamber (rather than just a copper plate), a new fan and plenty of aluminum to dissipate the heat. It also contacts everything that needs cooling (vRAM, MOSFETS and GPU).

One nick in the Mini’s armor is the thermal paste used. This stuff was hard to get off. It seems better, but similar to the stuff I complain about them using on their PCH chipsets. Put it this way, if you have to chip it off with your fingernail, I’ll take a wild guess and say it’s probably not premium thermal paste. It does its job though and let’s face it – from the cheapest to the best TIM you’re talking about a few degrees at most.

The GPU contacts a copper plate that then makes contact with the heatsink fins & fan on the other side. The rest of the heatsink assembly is made out of aluminum and contact comes courtesy thermal pads. Everything looked solid here, with good contact throughout.

ASUS says the heatsink is better and quieter than the reference design. Again, beware giant PR bars in graphs that don’t start at zero.

The fan is one you’ll see in a soon-to-come ASUS GTX 780 review. ASUS calls it their CoolTech fan and it is designed to be very efficient at blowing through lateral heatsink fins. It can also blow rice around well, apparently.

The PCB is obviously very compact. There is a lot of GPU here, just in a very small space. For anyone reasonably thinking this looks like the reference design but with a different heatsink, I assure you it is not. The PCB is wider (see how it extends a bit past the PCIe bracket) and skinnier. Here is MattNo5ss’ picture of the reference PCB. You can see how they saved some horizontal space in the power section and by switching to one 8-pin PCIe power plug, cutting off the rest of the PCB over there too.

DirectPower is an ASUS invention that gives a shunt instead of normal PCB traces between some parts residing behind the GPU.

A large shunt like this does typically have less resistance than PCB traces and will be cooler because there is a lot more metal to carry the current. ASUS’ marketing slide isn’t wrong on those points.

However, the utility of such a thing isn’t necessarily readily apparent. GPUs have been fine for years without such a thing, but it’s innovation and if manufacturers stopped trying to improve and kept churning out reference designs all the time, life in the GPU lane would be very boring. So kudos to ASUS for trying to improve, well, anything.

Moving on, we have the GTX 670 (GK104) itself.

As usual, ASUS has supplied this card with their Super Alloy Power components, consisting of upgraded chokes, stronger MOSFETs and capacitors behind the GPU (those are on most GPUs, not just ASUS).

Here is the power section itself. There are four power phases for the GPU and one for the memory. That’s not a ton, but with stronger components it should be sufficient. You can only fit so much on a GPU this size, so an excessively large power section wasn’t in the cards.

I’ve come to really like this next feature – red & green LED lights for power connectors to warn you when you have (and have not) plugged in the power on the GPU. Sure, for most people it’s a ‘duh’ thing, but I can remember back in the day being super excited to get something new and forgetting to plug in GPU power. If you do that, there’s a nicely placed red light to tell you where you went wrong.

Here are a couple more glamour shots and then we’ll get his thing in our test bed and see what it can do.

Test Setup

Typical of our test setup, we have a Haswell i7 4770K clocked at 4.0 GHz with RAM, courtesy G.Skill, operating at DDR3-1866/9-9-9-24. The competition runs the gamut of modern graphics card goodness.

The little Mini looks really cute on a full size ATX board. Remember, the Maximus VI Extreme is regular ATX this generation, not eATX, so this is how it will look on ATX and mATX width boards. This GPU was designed with mITX boards in mind, that’s for sure.

Overclocking

Overclocking the GTX 670 DirectCU Mini is somewhat easier than with other GPUs. Because of its size and smaller cooler, ASUS has taken the BIOS and essentially dropped its voltage tolerance. You can adjust Power Target, but not voltage. If you use a version of GPU Tweak that has that ability and you adjust the voltage, you’ll be met with worse scores/FPS because the GPU will be throttling all the time (believe me, I tried). So make sure you use the GPU Tweak version that comes with the card.

Thankfully, the little card did great when overclocking with just the available power tune limit. Now, it will be a bit louder with the fan spinning up, but it put out some great clocks, adding +150 MHz on the GPU and +1000 MHz (250 MHz actual) on the vMEM. Not too shabby for such a small card.

What that overclock translates to in actual use is an average of 1201.0 MHz throughout a run of HWBot Heaven Xtreme. For a tiny little card, those are plenty big numbers!

3DMark 11 even managed to break the 10,000 mark with this overclock.

Temperature and Power Consumption

Temperatures are obviously going to be on the higher side with such a small cooler, but it really didn’t do so bad for itself. The BIOS seems programmed to keep things around the 73 °C range and it does that well. Yes, it’s hotter than some other offerings, but it’s surprisingly quiet. The mass of aluminum on top of the copper does a good job at dissipation even when it’s relatively small. No complaints here – about temperatures (well within operating range) or volume (nice and quiet).

Power consumption comes in right where you would expect it to, trading blows with GTX 760s (which are a slightly cut down version of the GTX 670’s GK104 GPU).

Decent temps and as-expected power consumption. Continuing to look good for the little bugger.

Performance Results

You can see how we get our benchmark results by checking out our GPU Testing Procedures article, so I’ll spare you the lengthy details. Long story short – benchmarks are run at default and games are run at 1080p with all detail/AA/etc. turned up to the maximum.

Synthetic Benchmarks

I won’t blather on between graphs, but quickly summarize (yay for easy reading, right?). When benchmarking, the GTX 670 DirectCU Mini performs right where it should – right along side other GTX 670s and slightly better than the GTX 760. When overclocked it can even hang with the stock HD 7970.

Game Testing

There aren’t any surprises on the gaming front either as far as versus-the-competition goes. The biggest surprise to me was the Mini’s impressive gains when overclocking.

There won’t be any pushing the limits, because they’re already pushed. This card wouldn’t overclock any farther and when you try to put extra voltage to it, the GPU throttles near instantaneously (as it should to protect itself with the smaller cooler).

Final Thoughts & Conclusion

Now we’re to it – the final thoughts. This is usually my favorite part of reviews and this time it’s no different. As usual, we’ll start with price. The ASUS GTX 670 DirectCU Mini is out of stock right now at NewEgg but seems to sell anywhere from $300-$350 (up to silly prices you don’t need to worry about).

At $300 up to about $330, this card is a great deal, especially considering regular GTX 670’s on NewEgg right now are priced around $310+. You can get GTX 760s for less, but they aren’t as powerful as the GTX 670 even if they’re a little newer.

You may ask “why should I go with a GTX 6xx when the GTX 7xx series is here?” The quick & easy answer is that, unless you’re getting a GTX 780 ($600) or Titan ($1,000), the GTX 7xx contains the same GPUs as the GTX 6xx cards, so it’s kind of a moot point. If the GTX 760 was the same as the GTX 670, I’d say hold off, but it’s not – it’s ever so slightly cut down and that’s evident in our performance results.

If you’re insistent on holding off for the GTX 760, I did see on Facebook recently that ASUS announced they’re coming out with a GTX 760 DirectCU Mini. However, if you can find this card for $300, with its extra power, I’d recommend you take it and run.

This is the perfect card for SFF builders. The cooler works well and the power consumption is right where it should be for a card at this level. As long as you have decent case airflow, you will have a teeny, tiny card that gives big card results and doesn’t break the bank. What’s not to like?

Click the stamp for an explanation of what it means.

– Jeremy Vaughan (hokiealumnus)