I found out what was freezing Watch Dogs: Legion (can see it in task manager)

g67575

g67575

g67575

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I left task manager running on my 2nd monitor and I noticed that when the game freezes, the active time on the SSD I installed the game on reaches 100% and doesn't return to 'normal' until the game resumes again (usually takes about 30 seconds). When the freezing issue happens, the game is heavily writing to the page file and swap file.

The read access time of my BX500 Crucial 2TB SSD is apparently approx. 220 microseconds, so not the best. Other performance stats of the drive seem fine though.

The latest consoles use NVME drives, which have much lower access times (and we know Ubisoft doesn't put much time and effort into PC ports).

As far as I can tell, the VRAM was not a factor in this freezing, except that higher texture settings result in more data being read by the SSD.
 
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Yes, it can be played on 4K + Medium textures on my system without freezing. This made me think it was a VRAM issue before, but it's definitely the SSD.

In a way, I'm not that surprised, as the last Ubisoft AC game I played had problems with texture streaming on a hard disk drive.

WD Legions is a very odd game, I tried to load the page file onto a RAM disk, but the page file climbs to 10GB then crashes lol. Probably needs 11-12GB page file with the settings I'm using.
 
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So, has no one else had the problem with Watch Dogs: Legion? You need to set the game resolution to 4K, then enable High / Ultra Texture resolution in the game settings.

I suspect the issue doesn't occur on NVME drives.
 
The game loads all the game assets and textures onto the system's committed memory. Some of this committed memory will be the page file (virtual memory). I know this because if the page file is disabled, committed memory (now just 16GB on my system), is entirely allocated as the game loads into a level, then the game crashes.

In theory, another 8/16GB of system RAM would probably mean the game doesn't use the page file / disk to load textures at all, as all the committed memory can be physical RAM if the page file is disabled.

I don't have an SSD with DRAM cache (except a small OS drive), but feel free to test it. I haven't seen any evidence that suggests that there would be this kind of performance deficit with a DRAMless SSD (there seem to be a lot of assumptions about real world performance for some reason, even though most SSDs have an option to use system RAM as a cache for the SSD).

An SSD cache "caches the most frequently accessed data ("hot" data) onto lower latency Solid State Drives (SSDs) to dynamically accelerate system performance. SSD Cache is used exclusively for host reads". Link here:
https://mysupport.netapp.com/NOW/pu...UID-74019039-D7CD-4628-8BE5-334B47DD94BE.html

It's obvious that a NVME SSD (might as well get one with a DRAM cache too) would be the best bet though, to run the game without stuttering, why waste time on a sata drive? NVME drives have approx 5-10x faster read access times, and noticeably higher 4K read and write performance, compared to a Sata SSD with DRAM cache, example here:

https://www.elinfor.com/article/S/S/SSD (2).png
 
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The game is struggling to read files, not write them. NVME drives have better read access times, google it. I think we are arguing about nothing really, you say it's because of no cache I say it's slow access times, it could be either, we don't know.
 
Interesting. It does seem to be something to do with the SSD though, as the active time always reaches 100% on the SSD when it happens.
 
Right, I think I've found a solution. I had to defragment all the game's files using a trial program called Cobra file defrag (I tried Defraggler with only partial success). Link to download here:
https://www.cobraapps.com/products/filedefrag.php#:~:text=Cobra File Defrag employs an,free space on the drive.

I had to make sure there were no fragments in any of the game's files. I drove around the city for approx. 30 mins with no freezing, areas where the freezing usually triggered (like near bridges) were problem free. You might not believe that this can make any difference on an SSD, but some files it seems can be very fragmented (thousands of fragments spread across the drive). In the case of WD: Legions, it's files hard more fragmentation than any others on my PC.

I noticed that the game files were in a contiguous single block in Defraggler, after using Cobra to defrag the files.

So, it appears the old advice about not defragging SSDs just isn't true, sometimes it makes a large difference (but you need to do it selectively, not much point doing a 'normal' defrag). I wonder if this would help other games that suffer from similar problems?

Definitely the hardest game to get working, that I've played in many years.
 
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james.miller said:
Just make sure it has a cache. (it's fine, i know you'll ignore that advise).
Click to expand...

I have a 2TB SSD, I'm using what I've got and it works now, chill dude.

andybird123 said:
Why is there a massive argument about data drives in the GPU section?
Click to expand...
Friendly place, ain't it?

This guy explains the theory behind how file fragmentation can affect SSD performance, contrary to popular opinion. Each fragment of a file takes time for the operating system to access. Link here:
https://www.youtube.com/watch?v=VfYkJoqfG-k

I disagree with him that all files should be stored contiguously (he was trying to sell defrag s/w though), as technologies like wear levelling help to improve SSD lifespan.
 
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I fixed the problem I was having with the game, I'm sorry if that bothers you for some reason, or you cannot accept or believe it.

So, I may have written a few more GBs to the SSD, so what? The drive has an estimated TBW of 720.
 
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EsaT said:
Windows needs page file if there isn't enough RAM, because it's designed around having it.
That's why you shouldn't disable page file completely even if you have lots of RAM.
And pretty certain inability to expand page file size to match need causes also serious issues.
Click to expand...
I know, it was merely a test. Some games will always crash without one, some do not, it depends how they are programmed.
 
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VersionMonkey said:
Didn't see that until @EsaT quoted it.

Only thing I can say is that, whatever you thought you were trying to do, it was never, ever, going to end well.
Click to expand...

It's possible to just install more RAM tbh (but expensive), I don't think the game accessing the page file itself (regardless of which drive it's on) actually matters that much, the game files are what caused the gameplay freezing on my SSD.

I need to test the game a bit more to make sure the stuttering isn't happening after defragging the game files, but I played for a couple of hours last night and it was fine. One possible caveat, is that if the game files are changed with a game update, some of the files may need to be defragmented again.
 
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The freezing still seems to be happening occasionally unfortunately...

I've noticed that after the freezing occurs, the game loads more of the game files into the physical memory, reported as 'in use' in the Windows Resource Monitor. Initially, the game loads around 12GB, but it can rise to 13GB in some cases. I let the developers know about this SSD related freezing issue a few days ago, I guess there's a chance they might patch it still.

Also, the game gradually allocates a lot of RAM (5GB in my case) to 'standby' memory, where it tends to remain.
 
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I'm trying a tweak that preloads more system RAM into 'Standby' when loading into the game world, it now looks like this:

Standby-RAM.jpg
 
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