An Oculus PC on the cheap

OculusVR Minimum Rig Beauty

Power that’s not painfully expensive

Unless you’ve had your head under a rock for the past six months, you probably already know that virtual reality headsets–namely the Oculus Rift and the HTC Vive–are the new hotness when it comes to PC peripherals. VR is all over the media, but what keeps getting repeated over and over is that you’ll need a “high-end” PC to play games on the Rift or Vive.

I’ll be the first to say that the term “high-end” is relative. For PC gamers, high-end means i7 processors and graphics cards like the GTX 980 Ti and the R9 Fury. While such high-end parts will give you the best experience in VR, you can have an enjoyable experience without a $650 GPU, just like other games. So I set out to build a rig with the lowest-priced CPU and GPU that are certified to work with the Rift.

Choosing the parts

The official Oculus Rift minimum specification recommends an Intel i5-4590 Haswell CPU and a Nvidia GeForce GTX 970 graphics card. Without counting all the other parts needed, that’s a minimum investment of $500 to $580. (The i5-4590 is $200 and GTX 970s run from $300 to $380, depending on the model.) I thought I could do better.

To keep costs down, I decided to go with AMD parts. From testing, we know that the R9 390 scores higher than the GTX 970 in many benchmarks by about 15 percent. At $300, the R9 390 is a good buy, a small step ahead of the GTX 970. Additionally, the Oculus minimum spec says that a GTX 290 or better will provide enough performance for VR gaming. The updated 390 thus served our needs well, so I used a Sapphire Nitro R9 390 we had on hand for the system. The Nitro costs $330, though you can get more basic models for about $300.

OculusVR Minimum Rig Guts

When it came to the CPU, things got a little muddier. The official Oculus spec lists the i5-4590, but makes no mention of the minimum acceptable AMD CPU. After poking around, I found that the lowest-tier AMD FX processor that’s approved for use with Oculus Rift is the FX 6350. At $130, the FX 6350 isn’t a very high bar on the AMD side, but just a step above the FX 6300, a favorite of budget system builders. Higher-end AMD CPUs like the FX 8350 will do just fine. In fact, the AMD list of Oculus-capable CPUs all have at least six cores and a base clock speed of 3.9GHz.

Part Price
CPU AMD FX 6350 $130
GPU Sapphire Nitro R9 390 $330
Mobo MSI 970 Gaming $100
RAM 8GB Corsair Vengeance DDR3-1866 $45
SSD 240GB Adata XPG 2.5-inch SATA $137
HDD 1TB WD Black 7200RPM $74
Case SilverStone Raven RV05 $109
PSU Rosewill Photon 650 $90
Total $1,015 

At the approximate build price of $1,015 , the rig does seem a bit steep. However, you could save even more money by going with just the HDD, which would drop the PC’s price to $878. I’d recommend using an SSD anyway. The Adata drive is a bit pricey as SSDs go, and you can find a 250GB Samsung 850 Evo 2.5-inch SATA SSD for about $88. Using an 850 Evo instead of the Adata would drop the total price to $966.

You could drop the price yet further by using a more basic R9 390, which run as low as $305. You can always skimp more on the case as well, as some ATX mid-towers can go for as little as $50.

Dizzying flight

Building a “cheap” VR rig is great and all, but all that work doesn’t amount to a hill of beans if the PC can’t get the job done. And at first, this PC had me worried. After doing the initial setup of installing Windows, grabbing drivers, and doing all the other stuff I do before I start benchmarking, I still had to set up the Rift. And boy, was it annoying.

First of all, the Oculus system compatibility tool doesn’t list any AMD CPU as Rift-ready, even if it clearly isn’t the case. IF that wasn’t bad enough, the Rift refused to see my USB 3.0 ports as “compatible” when I plugged in the headset and sensor. These warnings persisted through setup, even after updating the motherboard’s BIOS, every driver I could find, and numerous reboots, unpluggings, and derogatory words.  I eventually gave up and decided to have a go at it anyway, full belly be damned. When in the menu right after putting on the headset, warnings appeared in the UI too. However, as soon as I started a game, everything seemed to work as expected.

SteamVR Test results on the budget system.
SteamVR Test results on the budget system.

As of yet, there aren’t a whole lot of built-in benchmarks to choose from when it comes to VR. For the HTC Vive, Valve offers the SteamVR Performance Test. When it comes to the Rift, there are even fewer choices. I settled on testing EVE: Valkyrie with FRAPS, since it’s included with the Rift and is more demanding than Lucky’s Tale.

To test EVE, I opened up Combat mode to engage in some dogfighting. While in the fight, I made sure to twist, turn, and look around the canopy as much as possible to test against any motion sickness that might arise from GPU performance. To capture quantitative data, I set FRAPS to capture frame times.

Frame times are a little different from the age-old frames-per-second measurement many gamers are used to. Frame times measure the time in between frames themselves, to better get an idea of any jitter that may occur. You can approximate FPS with frametimes as well. An evenly spaced sequence of frames at 100fps will have a frametime of 10ms, 90fps hit 11.1ms, and 80fps takes 12.5ms. Unlike FPS, frametimes improve as values shrink. (10ms is better than 11ms.) The target frame rate for the Oculus Rift is 90fps, so we’re looking for a scatter plot that places as many dots at or below the 11.1ms mark as possible

EVE Frametimes on Minimum Viable rig

As you can see, most of the little blue dots hover near the 90fps line. There is a noticeable smattering of frames that are falling above the line, but it’s not all bad. Given that they fall closer to 90fps than 80fps, we can infer that those frames equate to dips to about 85fps. That’s not bad, especially since the majority of frames are rendering at or below 11.1ms (or above 90fps).

In terms of how this felt, I didn’t really notice the frame drops, and enjoyed the battle as it raged on. (Never mind that my fighter was blown to bits and my body was exposed to the cold vacuum of empty space six times.) While chasing my foes, I made sure to bank hard and look up though my canopy. 

Looking at moving objects while your ship is banking, yawing, and pitching has the potential to make some sick by default. And I’ve played some demos that made me feel a little off. However, I didn’t experience any discomfort while playing on this system.

What does this all mean? In my eyes, this “minimum” spec build will get the job done as far as VR gaming is concerned. However, as more demanding games start to come down the pipe, this calculus could change. But for now, the R9 390 and the FX 6350 clear the launch tower.

Do try to dream a little bigger, darling

As well as the minimum-spec build did, doing the minimum isn’t always the best way to go about things. Our current top pick for GPU is the GTX 980 Ti, so I just had to build a rig that put Nvidia’s GPU to use. Instead of building the VR rig that I’d be comfortable playing with, I built a rig that I’d prefer to play with.

I started off the build with a “VR Edition” GTX 980 Ti from EVGA. The “VR Edition” isn’t much different from a typical EVGA 980 Ti with an ACX cooler, save for one modification: One of the card’s HDMI ports is relocated to the butt-end of the card (opposite of the I/O panel and venting). The reason EVGA put the port there is because the card comes with a front panel that fits into one of the 5.25-inch bays at the front of case. (This is usually where you’d install a DVD drive or fan control panel.) The panel has two USB 3.0 ports and one HDMI port. The USB 3.0 ports get plugged into your motherboard with a standard cable your case probably comes with, while the HDMI connects via an HDMI pass-through cable that fits into the oddly-located port on the 980 Ti. All of this adds up to an easy-to-access trio of ports for use with VR headsets. 

SteamVR Performance Test results for our ideal GTX 980 Ti system.
SteamVR Performance Test results for our ideal GTX 980 Ti system.

I pared the 980 Ti with an Intel Core i7-6700K Skylake processor. The 6700K is unlocked, so I installed a Corsair H80i v2 to keep the brains of the PC cool. I filled the rest of the build out with 16GB of DDR4-2666, a 250GB Samsung 850 EVO 2.5-inch SATA, two 1TB WD Blacks, a Corsair CX500 PSU, and an MSI Z170A mini-ITX mobo. I stuffed (and I mean stuffed) all of this into a BitFenix Prodigy M micro-ATX case.

While I really love building mini-ITX rigs, there are always annoyances. First off, the Prodigy M comes with two case fans pre-installed. That’s nice and all, but the mini-ITX motherboards rarely have two chassis fan PWM pinouts. (I can’t remember the last time I’ve seen one, anyway.)

The other thing to know is that this case was a tight fit. I originally wanted to use an EVGA NEX 650W modular PSU, but the PSU was just too long, and kept me from installing the GPU. Cable management in this case was also a nightmare, as was trying to install the big, blocky H80i.

But it worked.

And all things considered, the rig is a compact, portable rig that doesn’t take up much room. I’m okay with that.

The takeaway

If there’s one thing to learn from these two builds, it’s that a wide range of gaming PCs will be able to serve up video to the Oculus Rift. That said, there are plenty of gamers with older CPUs and GPUs that may find that it’s time to upgrade.

AMD fans are in for a treat, since their upgrade path is considerably cheaper. AM3+ motherboards go clear back to 2012, while the 90-series Intel chipsets that the i5-4590 requires was released in 2014. That means if you’ve got an older Intel box, you may have to upgrade your motherboard too. Older AMD boards may get away with simply replacing a CPU. But even as you upgrade the CPU, you don’t need to go crazy, at least not for VR.

Steam, please tell me who owns a Haswell-E system with an R7 360 GPU.
Steam, please tell me who owns a Haswell-E system with an R7 360 GPU?

One thing that’s abundantly apparent in VR is that the GPU does the lion’s share of the heavy lifting. While there are CPU requirements for the Rift, they aren’t terribly demanding. If you’re making an upgrade decision, spend the money on a good, solid GPU. If you can afford an R9 390, great. If you can afford a GTX 980 or a R9 Fury, even better. A GTX 980 Ti is best. 

There are plenty of Oculus-Ready PCs coming to market, but upgrading your current system can save you hundreds. If you’re planning on building a new system for VR, I’d hold off for now. Both Nvidia’s Pascal and AMD’s Polaris chips could make debuts in 2016. It will be worth it to hold out for the newer chips, or potential price reductions for current-generation GPUs.

It’s also important to note that the Rift itself will set you back $600. There aren’t a whole lot of games (compare to your Steam library) to choose from on Oculus yet, and the HTC Vive has yet to ship to customers. With such steep barriers to entry, patience might be the biggest asset for those wanting the best VR experience.

Source

Hardware, HTC Vive, Oculus Rift, vr

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