Can any games these days be reliably ran on hdd's with max 200mb/s throughout (at best)? Or does everyone get a coffee and some cookies when a new zone loads? Even with this reduction that will take a while.

I thought all required ssd's now for "normal" gameplay.

Until you get to super-high-res textures and the like, the throughput isn't nearly as important as the latency.

At 200 MB/s the way hard drives usually measure it, you're able to read up to 390,625 512-byte blocks in 1 second, or to put it another way, a block that's immediately available under the head can be read in 2.56 microseconds. On the other hand, at 7200 RPM, it takes up to 8.3 milliseconds to wait for the platter to spin around and reach a random block on the same track. Even if these were the only constraints, sequentially arranging data you know you'll need to have available at the same time cuts latency by a factor of about 3000.

It's much harder to find precise information about the speed of the head arm, but it also usually takes several milliseconds to move from the innermost track to the outermost track or vice versa. Also, since hard drives are so large nowadays, the file system allocators actually tend to avoid fragmentation upfront, leading to generally having few fragments for large files (YMMV).

So, the latency on a hard drive can be tolerable when optimized for.

> On the other hand, at 7200 RPM, it takes up to 138 microseconds to wait for the platter to spin around and reach a random block on the same track.

You did the math for 7200 rotations per second, not 7200 rotations per minute = 120 rotations per second.

In gaming terms, you get at most one or two disk reads per frame, which effectively means everything has to be carefully prefetched well in advance of being needed. Whereas on a decade-old SATA SSD you get at least dozens of random reads per frame.

Fixed!

"Self fulfilling prophecy" perhaps?

> 154GB vs 23GB can trivially make the difference of whether the game can be installed on a nice NVMe drive.

I think War Thunder did it the best:

  * Minimal client 23 GB
  * Full client 64 GB
  * Ultra HQ ground models 113 GB
  * Ultra HQ aircraft 92 GB
  * Full Ultra HQ 131 GB

For example, I will never need anything more than the full client, whereas if I want to play on a laptop, I won't really need more than the minimal client (limited textures and no interiors for planes).

The fact that this isn't commonplace in every engine and game out there is crazy. There's no reason why the same approach couldn't also work for DLCs and such. And there's no reason why this couldn't be made easy in every game engine out there (e.g. LOD level 0 goes to HQ content bundle, the lower ones go into the main package). Same for custom packages for like HDDs and such.