I've heard many guitarists in this genre, but unfortunately none of the guitarists had satisfied me. Many of their leads sound sloppy and horrible(most of them are limited by pentatonic scales and not more) when they try to play something fast and technical. Can you suggest some technically skilled ones (those who can play sweeps, fast scale runs, 8 finger tapping licks etc.)

P.S. I've heard of Scolnick, Mustaine, Friedman, Holt, Waters, Atlus.

Круиз

ron jarzombek of watchtower would be an obvious one

Paul Gilbert

You my friend, need Josh Christian (of Toxik fame) in your life. Now, not only are both World Circus and Think This two of the best tech thrash albums ever, but Christian might also be the most skilled thrash guitar player to ever walk the earth. He can do it all; shred with the best of them, beautifully implement acoustic sections into the music, and rip out the occasional ultra-melodic-but-extremely-badass solo. I think you'll like him

Check out David Davidson of Revocation. They incorporate elements of death metal and a tiny bit of core stuff but it's done tastefully and he's a phenominal guitar player. Worth looking into if you like that type of stuff.
http://revocation.bandcamp.com/album/sc ... atogenesis

my favourites (josh and ron j) have been already listed so i´ll go with something more recent...
david di santo and erik nelson from vektor are two guitar maniacs, their riffing and solo lines are mind blowing
but what´s even more important, they sound fresh and innovative.

The guys from Hexen also rip some awesome riffs and licks, check out their latest album Being and Nothingness.

I don't know much about this band yet, but I'd recommend Suicidal Angels, because you already said you know all of my other suggestions XD
https://www.youtube.com/watch?v=UYDAVT8c1JE

Some parts might be what you're looking for...

Tommy T. Baron

http://www.youtube.com/watch?v=RSgzBJWYVso

total fucking classical obliteration!

Annihilator or Testament probably.

There's a band called Blind Illusion, who only released one album in 1988. Ron Biedermann is an amazing soloist. And to top it off, the band features Les Claypool and Larry LaLonde (no slouch himself, by the way) of Primus!

http://www.youtube.com/watch?v=GCRkCPSz2M0

Wow! That's what I'm talking about. Those schizophrenic riffs and solos are the best thing I've ever heard in my life. Control and Resistance is definitely one of the best tech metal releases. And the drummer is the best in whole genre. Thanks a bunch.

HOLY FREAKING MOTHER! Sir, you made my life happy again! That second album is the most amazing thing ever released on this earth. That lead work is simply unbelievable. None of other guitarists had ever impressed me as much as this one. He's my idol now. I think I need nothing more. Thanks a lot.

Hey, glad you liked him and his music so much! Those two albums are lost classics and surely deserve more attention

And dont forget the guitar duo from Artillery on their best effort, By Inheritance!

Glad to see this mentioned here. Valeriy Gaina is an unsung hero for sure. 1988 album is a good place to start.

Jeff Waters is a killer guitarist !

http://www.youtube.com/watch?v=vm3YdCYuOVo

some newer ones that come to mind are Havok and Holy Grail.

Wow, now I'm going to have to go and check that out myself.

along the lines of Watchtower and Toxik for technical thrash, maybe check out Vektor
http://www.youtube.com/watch?v=1tAbcWrrIQU

or Coroner
http://www.youtube.com/watch?v=YMGF_nvZhJ0

Invocator, for sure!
https://www.youtube.com/watch?v=S7_qysJ6M2g
For speed metal, I strongly suggest Helstar (especially the Distant Thunder and Nosferatu albums, https://www.youtube.com/watch?v=346P6Hye92s), Agent Steel and Intruder https://www.youtube.com/watch?v=LWdviPHIJ2g