27" Retina iMac First Impressions

I just received my 27" Retina iMac yesterday and figured I would post my impression so far.

The Display

The most exciting thing about the new 27" Retina iMac is the display.  It runs as 5120x2880 resolution which is 4x the number of pixels as the Apple Thunderbolt Display and non retina 27" iMac.  The higher resolution of the retina display is of specific interest to diagnostic radiology as it will allow high resolution images such as chest x-rays and mammograms to be displayed at full resolution.  Displaying these images at full resolution is important because it eliminates the need for the radiologist to zoom and pan the image thus saving time. 

After starting up the Retina iMac for the first time, I was a bit disappointed because I didn't really notice that much of a difference compared to the Thunderbolt Display. It certainly wasn't any worse - the display is just as beautiful and bright as any other Apple display, but nothing stood out as amazingly got to have it better. It did "feel" a bit different but it was hard to quantify.  I knew it was higher resolution so looked around for more detailed icons and text and convinced myself it was better when I looked - but the difference is quite subtle.  

One thing I was relieved to discover is that the display does in fact run at 60hz.  I had tried out another display earlier this year that could only do 30hz and it was unusable for me.  I had read one review about the retina display claiming that it only did 30hz but that is definitely not the case.

Interestingly enough, I have really noticed the improvement in resolution while writing this blog entry.  The text is much sharper and it feels like reading a book.  I have the feeling that the benefits of the display will be clearer when after I get used to it and then look at a non retina display.  I had a similar experience with the retina iPhone - not initially impressed but very hard to go back to a non retina device.

The Video Card

The Retina iMac comes with an AMD Radeon R9 M290X with 2 GB RAM or an AMD Radeon R9 M295X with 4 GB RAM.  There was some concern online about how well the system would handle 4x the pixels to push around.  I am happy to report that it handles it just fine - I haven't noticed any drop in performance - in fact, it feels faster than my 15" Retina Macbook Pro did connected to the thunderbolt display.  I have noticed two issues so far - one is that youtube videos would not playback at full screen (I could hear audio, but the screen was black).  This one seemed to have fixed itself, so it may have just been a glitch.  The other is that World of Warcraft seems to stutter in some places. This stuttering is really annoying and feels like a software bug in the game or video driver that will hopefully be fixed in the near future.

The CPU

According to Geekbench, the Retina iMac is the fastest Mac available today for single core work and is only beat by the high end Mac Pro for multicore work.  The machine certainly feels fast, I was playing WoW with two Windows 7 virtual machines running in the background and didn't even notice it.  The only drawback to this system is the fan is louder than I like.  The fan turned on while I was playing WoW and the noise was noticeable.  Not as loud as the fan on my MBP, but still loud enough to be annoying.

I also tried out the window/level operation on a full resolution mammogram using cornerstone and it was able to keep up at about 20 FPS which is a bit lower than I would like but fast enough for most users.

The Flash Drive

The new iMac comes with a PCIe Flash Drive.  I was hoping that it would have similar performance to the rMBP but was disappointed to learn that it is quite a bit slower.  It is faster than a SATA SSD drive, but not by much.  Here is a screenshot from running blackmagic: