Running a 4k screen using a Radeon HD 5450
I was the lucky recipient of a 4K monitor recently (an ASUS MX27UQ). So the question of how to drive it arose.
In order to run it at its full resolution of 3840×2160, with a 60Hz refresh rate, I assumed I was going to need a new graphics card, so started looking around. I wanted something fairly low powered (I only have a 150W power supply), silent and less than £50.
It quickly became apparent that I would need a DisplayPort 1.2 card, which supports that resolution. The most common HDMI standard at the moment is 1.4, which only supports 3840×2160 at 30Hz. There are very few HDMI 2.0 cards available (which supports 60Hz), and they’re all very expensive.
I wasn’t looking to do any gaming, so didn’t need anything very powerful. I was looking for cheap and quiet. That combination proved elusive though, with most cards either having a fan, not enough resolution, being quite expensive or no longer available.
I was leaning towards a new motherboard as the cheapest option. This MSI board seems to have all the right specs and I almost bought that, except I realised it’s the CPU that’s responsible for the graphics and my G3258, which doesn’t even have a version on its Intel HD graphics, wasn’t going to cut it. I’d need to buy an i3 chip at least, which made the whole bundle way more expensive than a graphics card alone.
I considered an external, USB option, such as the Plugable USB 3.0 to DisplayPort 4K UHD. I was close to pulling the trigger when I realised it was only 30Hz, despite being DisplayPort. It was cheaper than most of the internal options though.
During my research I found some suggestions that even a Radeon HD 5450 could output the required resolution, albeit at only 30Hz. I figured if I was only going to get 30Hz (without spending more than I wanted and/or sacrificing to noise), I might as well explore this option. There was this comment on a VisionTek card, for example. There was also this thread at Hard Forum. There were other places too, but every time I checked the official stats on manufacturer’s websites they said otherwise. Even AMD’s own spec sheet says otherwise.
I already had this Sapphire HD 5450 card already, running my 30″ screen, but I couldn’t pick anything higher than 1920×1080 when I plugged my new screen into the HDMI port. I wondered if I could force a higher resolution somehow. Neither the Windows tools or Catalyst Control Center would let me pick it or create a custom resolution.
That led me to an application called Custom Resolution Utility (CRU), which fills in the hole left by all the default software. As it turns out, the resolution I wanted already appeared in the list it exposed. The notes in that forum post suggested I would need to patch my driver to allow a faster pixel clock. This allows for higher resolutions and refresh rates.
The notes included a link to something called the AMD/ATI Pixel Clock Patcher. It was simple enough to run and, immediately after patching it and restarting the driver (using the tool supplied with CRU) I was able to pick 3840×2160 (at 30Hz) from the resolution option in windows.
I’m limited to 30Hz because it’s connected via an HDMI port, but it’s perfectly liveable. The other bonus is I can still run my 30″ at full resolution too. All without spending any more money.
If you’re not a gamer, but want to make use of 4k, it’s worth a look into what you can force your current card to do, as you might be surprised. This is a GPU that was released in 2009!