Apple seeded OS X 10.9.4 (Build 13E9) to registered Mac developers, made available through their Software Update mechanism in the Mac App Store, as well as through the Mac Dev Center.
Other people can get the developer preview with help of this blog article.
The most interesting part is the addition of three new resources (plist) files for power management:
Mac-81E3E92DD6088272.plist / iMac15,1 (IGPU only)
Mac-42FD25EABCABB274.plist / iMac15,n (IGPU/GFX0/Apple display with id 0xAE03)
Mac-FA842E06C61E91C5.plist / iMac15,n (IGPU/GFX0/Apple Retina display with id 0xAE03)
This is based on the perf-bias value of 0x1 (highest performance) which happens to be the same as the current iMac14,n models – all other Mac models use 0x5 and 0xf. Unsurprisingly, of course, since Apple doesn’t want you to drain the battery flat in say two hours.
The EDID data for the GFX0 display is set to a screen size of 60 x 34 CM but the resolution data is blank.
I compared some of the data in OS X 10.9.3 with OS X 10.9.4 (Build 13E9) and found some additional changes. Some of which may indicate that the new iMac may have a Retina LCD. Which would be awesome.
spdisplays_vram_shared = “VRAM (Dynamic, Max)”;
spdisplays_retinaLCD = “Retina LCD”;
spdisplays_airplay = “AirPlay”;
spdisplays_airplaydisplay = “AirPlay Display”;
spdisplays_projector = “Projector”;
spdisplays_virtualdevice = “Virtual Device”;
spdisplays_captured = “Display Captured”;
spdisplays_donotdim = “Do Not Dim”;
spdisplays_stereo = “Stereo”;
spdisplays_1080p = “1920 x 1080 @ 60Hz (1080p)”;
spdisplays_1080i = “1920 x 1080 @ 60Hz (1080i)”;
spdisplays_720p = “1280 x 720 @ 60Hz (720p)”;
spdisplays_true480p = “704 x 480 60Hz (480p)”;
spdisplays_480p = “720 x 480 60Hz (480p)”;
spdisplays_480i = “704 x 480 60Hz (480i)”;
spdisplays_displayport_adapter_nonapple_dual-link_dvi = “Mini DisplayPort To Dual-Link DVI Adapter”;
spdisplays_displayport_adapter_nonapple_vga = “Mini DisplayPort To VGA Adapter”;
kHW_IntelIrisItem = “Intel Iris”;
kHW_NVidiaGeForceGTX750MItem = “NVIDIA GeForce GT 750M”;
kHW_AMDFireProD300Item = “AMD FirePro D300”;
kHW_AMDFireProD500Item = “AMD FirePro D500”;
kHW_AMDFireProD700Item = “AMD FirePro D700”;
Apple uploaded a new version of OSXUpdCombo10.9.4.pkg (Build 13E9a) but all I could find out so far was that some of the installation scripts and SystemVersion.plist was touched – no changes were made to the mach_kernel, frameworks or kexts. It did also not show up as a new update in the App Store, so it is, apparently, not intended for people with Build 13E9 installed. It also won’t install over builds: 13A598, 13D65 and of course 13E9a.
Edit: I also added two small screenshots.
Apple changed some of the data in OS X 10.10 Yosemite Developer Preview. They also added a new display override file: /System/Library/Displays/Overrides/DisplayVendorID-610/DisplayProductID-AE03 so guess what. One of the to-be-released iMac’s will have a Retina LCD. It’s the one with board-id: Mac-FA842E06C61E91C5 ;)