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Oblivion BSA Decompressor by zilav


Malonn

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This mod was released to the Nexus today.  This brings a question to mind: Does compression hurt performance?  The release of the utility suggests the author believes so, but is his thought correct?  I read once by Ethatron that modern CPUs actually take less time/cycles to decompress than they do to load uncompressed files.  I would think it would take more time to decompress first, BUT Ethatron backed his findings with numbers.  zilav points to I/O in his description, so is that where the difference resides?  I know a SSD/HDD read-write call takes forever compared to an CPU cycle.

So, could I get some more info?  What's true?  I will start running uncompressed BSAs from now on if it helps.

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This had been run through extensive testing back in the heyday of Oblivion and it was found that uncompressed BSA files make only a very marginal difference that even then wasn't worth the bother on modern hardware of the time. With as much as hardware has advanced since then I doubt very much you'd notice a benefit from this at all.

Unfortunately I don't think the posts where this issue was discussed still exist, but you can try digging around at the old forum at forums.bethsoft.com and see what you can find. I'll go poke around for a bit myself in a little while.

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I can see this being helpful for players on older machines with mechanical hardrives and large load orders. Exterior areas would probalby see some benefits. This utility technically only changes five files.

DLCShiveringIsles - Faces.bsa (USIP file)

DLCShiveringIsles - Meshes.bsa

DLCShiveringIsles - Textures.bsa

Oblivion - Meshes.bsa

Oblivion - Textures - Compressed.bsa

I wasnt too fond that it only works on installs that are outside of Program Files, but I was able to work around that easily. 

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That's what I thought.  I guess I was confused (optimistic?) by a programmer like zilav releasing a utility like this.  You would think he's done research into the topic, but perhaps he just felt like programming something...

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The 4th addendum in this post here is probably what you want: I had forgotten we even cloned the post here. It was originally geared toward Skyrim but the BSA basics it gets into in section 4 should apply to Oblivion as well.

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The old tests mentioned here are subjective, they are based on human perception only. Recently New Vegas has been profiled with debugging software to test in which code parts the engine spends the most time and zlib code had a significant weight, and this is an objective test. In other words - the fact. That's why New Vegas decompressor was made first a year ago. We even pushed forward and also utilize ESM decompression now (half of the game master is compressed with zlib) to completely get rid of zlib bottleneck in the engine. Decompression showed performance increase both objectively (through profilers) and subjectively (stutter perception while playing) by proficient mod authors in New Vegas modding scene and users. It is an integral part of TTW and has been extensively tested by dozens of thousands of users for almost a year as of now, and I can say with all assurance that decompression didn't cause any issues.

People asked for same feature for Oblivion, that's why I made it. Considering that FO3/FNV are very similar to Oblivion I don't see why it won't help with performance here too. But I'm not forcing anyone to decompress their files, I don't even advise that anywhere. I didn't make any forum/reddit/news posts, simply uploaded it for people who asked for and want to use it.

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Another OCD for those who pursue μs disk tweak economy is physical location on the disk. Repacking the BSAs may position them on a cluster further away than that of the exe, thus incurring a small penalty in seek time.

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Thanks for the responses.  I'm willing to try both compressed and uncompressed.  I've always run compressed because of Ethatron's old post, but objective results speak for themselves.

@lmstearn that is serious OCD!  Moving the bsa closer to the exe is hardcore.  I run an SSD though, so shouldn't affect me.

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