1. What is the 64-bit client for Mac?
As of ESO version 2.3.0 (the first PTS build for the Thieves Guild DLC)
the Mac client is now 64-bit only. The old 32-bit version is
discontinued, and no longer available. The Launcher will
always launch the 64-bit client binary, which is now the sole executable file within the game's Mac client repository.
Switching to a 64-bit memory model greatly increases memory management stability, as more memory can be used by the client process during runtime. This implies that
only systems with more than 4 GB of RAM are really able to profit from it, as is stated in the
2.3.5 patch notes:
Machines with 4GB of RAM may see a negative effect on game performance.
With the new 64-bit client came the switch to a
new OpenGL 4.1 rendering engine, which greatly improves graphics performance (e.g., only one pass is now needed to render the ground, instead of two with the old client).
Please note that the quality of textures on the High Quality setting has been improved as well -- while the game surely looks better with them, they also need more memory.
Systems with only 4 GB of RAM, less than 2 GB of video RAM and/or integrated processor graphics (IPG) will most likely need to tune texture quality down from High Quality, even if the game ran with these settings prior to version 2.3.
Please also note that the switch made it necessary that
shaders now have to be compiled on demand, as they are no longer able to be cached on disk in a compiled state.
This inevitably leads to longer loading screens, but can be alleviated by using any version of OS X/macOS above Mavericks (10.9), as the latter is way slower at this than its successors.
2. What does my Mac need to run it?
First and foremost, your machine at the very least needs to meet the requirements of the
minimum system specifications for Mac -- all of them. The most important ones are,
en detail:
- An OpenGL 4.1 compatible graphics card (GC) or IPG. Please refer to this compatibility chart from Apple to see whether your Mac's GC supports it. If your GC does not list OpenGL version 4.1 as being supported, you're no longer able to play ESO on this machine (you might want to try Boot Camp, but then your GC needs to support DirectX 11 at the hardware level on Windows Vista and up).
- At least OS X 10.9 Mavericks for OpenGL 4.1 support, but any OS X/macOS version from 10.11 El Capitan onward is greatly recommended for the reasons stated above in section 1). All machines that are able to run Mavericks can run El Capitan as well (some newer OS X features like Continuity or Air Drop might not work due to missing or incompatible hardware components).
- More system memory (RAM). If it is at all possible to upgrade RAM on your Mac, then do so, especially if you're sitting on 4 GB only. 8 GB will be a game changer and is the new recommended minimum amount of RAM (as per 2.3.5 patch notes). 16 GB is comfortable for all intents and purposes. 32 GB should not be necessary, unless you run lots of other stuff in the background.
- A minimum of 1 GB VRAM (video RAM) on your Mac's GC. If your Mac has IPG, it will always use a portion of the system RAM as its video memory (called unified memory), which in turn will then be unavailable to the system and the game. Please refer to your Mac's documentation whether the IPG's maximum unified memory size is able to exceed 1023 MB at all. In most cases, the amount of unified memory made available as VRAM depends on the total amount of RAM installed. Caveat: if you're using a multiple monitor setup, especially with one or more Retina displays attached, VRAM available to the client might fall below the threshold of 1 GB, as the GC's or IPG's VRAM is split up between all active displays.
3. General performance tips
- As with every new patch, update your addons if available, or disable them for the time being. Running with outdated addons might lead to frequent crashes, as they will need to be adapted to changes to the game and its LUA API.
- Reset the Video Settings to their default, by pressing [X] in the settings menu.
- Run the game in Fullscreen mode -- not Fullscreen (Windowed).
- Always (yes, always) turn VSync OFF!
- Tune down Shadow Quality and View Distance, they might be set too high by default. The game still looks great on Medium/ <= 50.
- Due to the improvement of High Quality textures, you might want to try to take Texture Quality down a notch to increase frame rates. If your Mac has only 4 GB of RAM, you might need to.
4. Current workarounds
Hope this helps.
Edited to incorporate changes after the the first incremental
patch 2.3.6 on March 14th, 2016.
Edited to estimate the impact of changes of
patch 2.3.7 on March 21st, 2016 (section 4).
Edited on May 18th, 2016 to update post as the game moves toward version 2.4 (Dark Brotherhood DLC). Incorporated Mac-relevant changes from 2.3.8 to 2.3.11 and 2.4.0_PTS to 2.4.3_ PTS (if any), if they regard the 64-bit client explicitly. Removed old and now obsolete workarounds. Updated section 2 to reflect changes on minimum specs. Minor clarifications of wording.