[Carti-it]

Method	a	b	Mean	Error	StdDev	Ratio	RatioSD	Allocated	Alloc Ratio
ArrayEqual_Master	Byte[0]	Byte[0]	0.8767 ns	0.0168 ns	0.0157 ns	1.00	0.02	-	NA
ArrayEqual_PR	Byte[0]	Byte[0]	0.4866 ns	0.0270 ns	0.0252 ns	0.56	0.03	-	NA
ArrayEqual_Master	Byte[0]	Byte[1]	1.5359 ns	0.0430 ns	0.0402 ns	1.75	0.05	-	NA
ArrayEqual_PR	Byte[0]	Byte[1]	0.4870 ns	0.0127 ns	0.0112 ns	0.56	0.02	-	NA
ArrayEqual_Master	Byte[1]	Byte[1]	1.4931 ns	0.0406 ns	0.0380 ns	1.70	0.05	-	NA
ArrayEqual_PR	Byte[1]	Byte[1]	1.0676 ns	0.0187 ns	0.0166 ns	1.22	0.03	-	NA
ArrayEqual_Master	Byte[2]	Byte[2]	2.0147 ns	0.0723 ns	0.1082 ns	2.30	0.13	-	NA
ArrayEqual_PR	Byte[2]	Byte[2]	1.7478 ns	0.0227 ns	0.0213 ns	1.99	0.04	-	NA
ArrayEqual_Master	Byte[3]	Byte[3]	1.3874 ns	0.0204 ns	0.0181 ns	1.58	0.03	-	NA
ArrayEqual_PR	Byte[3]	Byte[3]	1.0474 ns	0.0202 ns	0.0179 ns	1.20	0.03	-	NA
ArrayEqual_Master	Byte[5]	Byte[5]	3.9556 ns	0.0566 ns	0.0501 ns	4.51	0.10	-	NA
ArrayEqual_PR	Byte[5]	Byte[5]	3.2429 ns	0.0727 ns	0.0680 ns	3.70	0.10	-	NA
ArrayEqual_Master	Byte[6]	Byte[6]	3.9994 ns	0.0537 ns	0.0449 ns	4.56	0.09	-	NA
ArrayEqual_PR	Byte[6]	Byte[6]	3.7730 ns	0.0481 ns	0.0450 ns	4.30	0.09	-	NA
ArrayEqual_Master	Byte[32]	Byte[32]	21.1504 ns	0.3606 ns	0.4008 ns	24.13	0.61	-	NA
ArrayEqual_PR	Byte[32]	Byte[32]	18.9925 ns	0.2618 ns	0.2449 ns	21.67	0.46	-	NA
ArrayEqual_Master	Byte[32]	Byte[32]	1.4625 ns	0.0593 ns	0.0812 ns	1.67	0.10	-	NA
ArrayEqual_PR	Byte[32]	Byte[32]	1.2298 ns	0.0190 ns	0.0178 ns	1.40	0.03	-	NA

[Carti-it]

Originally, I was interested in

+#if HAS_SPAN
+			return a.AsSpan().SequenceEqual(b);
+#else
			return ArrayEqual(a, 0, b, 0, a.Length);
+#endif

but it behaves like this

Method	a	b	Mean	Error	StdDev	Ratio	RatioSD	Allocated	Alloc Ratio
ArrayEqual_Master	Byte[32]	Byte[32]	22.2745 ns	0.4059 ns	0.4832 ns	24.86	0.64	-	NA
ArrayEqual_PR	Byte[32]	Byte[32]	3.6044 ns	0.0907 ns	0.0848 ns	4.02	0.11	-	NA
ArrayEqual_Master	Byte[32]	Byte[32]	1.3504 ns	0.0594 ns	0.0851 ns	1.51	0.10	-	NA
ArrayEqual_PR	Byte[32]	Byte[32]	2.9751 ns	0.0841 ns	0.0826 ns	3.32	0.10	-	NA

So for byte arrays that are equal it goes from 22 ns -> ~4 ns but it's worse for non-equal byte arrays. I guess non-equality is in general more common. One would have to go into "amortized time complexity"... well, I guess I cannot win with it.

[NicolasDorier]

why not

if (a.Length != b.Length)
				return false;

[Carti-it]

It should be like that. I fixed it.