Nothing but, Precompression is necessary. If you are use a precomp,Just try with brute option. What is difference between precomp and precompx?
Ans : Precomp is not a chunk based compression. But precompx is a chunk based compression. Set chunk size in 128 Mb getter good precompression. Plot twist precomp is faster to infalte the files. Precompx was little bit slow.
2. Which external compressor suitable for better compression?
4 types of tools are available. There are
* BWT (Faster to compress)
* CM (Compression and decompression time equal) Ex: MCM,Nz
* Paq (Ultra compression,but time takes more) zpaq,paq8 etc
* lz based compression (lzma,lolz,rz,dlz,xz) Gives better ratio

Every better compreesion based on your Precompression and srep parameters only

3. Why lolz gives high compression ratio?
Because it detects the raw dds and dxt files.

I recommend to use rz or nz. Set rz dictionary size 128m to get better ratio. Also decompression speed is awesome.

Well explained. Thank you for this good info

What is BWT? I don't have that in the DB yet, nor in my ini

BWT=Burrows-Wheeler Transformation. (AFAIR BCM/BSC is a BWT compressor)

IMHO SRep-LOLZ is the best.
Or the LDMF capable LOLZ,(22c4b) but sometimes i face bugs. (Unable to decompress in the middle of the progress for example)

Srep + LOLZ ... very good.

LDMF capable LOLZ, (22c4b)

I have LOLZ and another version of it.

That LDMF DEC has. Long Distance Match Finder. Ok.

I'll test it against each other.

Whao, LOLZ have many many Options...what is the best

My Arc for both Lolz:

[External compressor:lolz]
header = 0
packcmd = "lz\lolz_x64.exe" -mmt1 -mt4 -mtb512 -rt2 -mc256 $$arcdatafile$$.tmp $$arcpackedfile$$.tmp
unpackcmd = "lz\lolz_x64.exe" $$arcpackedfile$$.tmp $$arcdatafile$$.tmp

[External compressor:lolzi]
header = 0
packcmd = "lz\lolz2_x64.exe" {options} $$arcdatafile$$.tmp $$arcpackedfile$$.tmp
unpackcmd = "lz\lolz2_x64.exe" $$arcpackedfile$$.tmp $$arcdatafile$$.tmp

Can someone please show me a good Arcini for these two LOLZ?
I think I set something wrong with my LOLZ. The compression is canceled. With the LDMF it runs normally.

Another problem has emerged:

I can pack LOLZ and RAZORX, but I don't get a file when unpacking. So something is wrong there.

What is wrong with that?