The benchmark was carried out on a 800MHz Pentium III with 1Gb of RAM. You can download the list of the polynomials used in the benchmark. Some nfgaloisconj records:

degree	timing	output	polynomial
160	49mn	3850 kb	polcompositum(x^20-2,polcyclo(20))
192	1h, 47mn	4873 kb	polcompositum(x^24-5,polcyclo(24))
220	1h, 24mn	841 kb	polresultant(x^22-2,subst(polcyclo(22),
			x,(a+2*x)*x^21/2))*2^10
252	1h, 7mn	922 kb	polresultant(x^21-2,subst(polcyclo(21),
			x,(a+x)*x^20/2))*2^12
336	12h 12mn	2581 kb	polresultant(x^28-2,subst(polcyclo(28),x,(a-2*x)*x^27/2))*2^12

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