no the standart 5150 is very bad.. it harms your environement :D
reality shows, that there is not "THE AMP" out there.. its in your finger, and how you play those fukkin palmmutes.. overall tightness is the main problem of any serious deathmetal giutarist. so it's primary not the sound of the amp, witch is the problem, it's the technique and overall performance.
long story short:
try out Laboga Mr. Hector, with the d'addario? pickup booster or an old (IMPORTANT!) ibanez tubescreamer.
old!! MEsa boogie dual recto. mod it's FX way and put some tubes in there (KT or something).
old Marshall JSL
old peavey 5150, heavily modified with NOT THE STOCK TUBES.
I don't know why not any single manufacturer, can produce a good amp out of the factory these days (Laboga seems to be a big exception).
good luck man..
keep on practicing