Some lga socket nonsense

Harpertown Xeon equivalents

Model	Xeon equivalent	Difference
Q8200	E5410 L5410	E5410: Lower TDP (80 vs. 95W), More cache (12MB vs. 4MB) L5410: Lower TDP (50 vs. 95W), More cache (12MB vs. 4MB)
Q8200S	E5410 L5410	E5410: Higher TDP (80 vs. 65W), More cache (12MB vs. 4MB) L5410: Lower TDP (50 vs. 65W), More cache (12MB vs. 4MB)
Q8300	E5420 L5420 X3320	E5420: Lower TDP (80 vs. 95W), More cache (12MB vs. 4MB) L5420: Lower TDP (50W vs 95W), More cache (12MB vs. 4MB) X3320: Same TDP, More cache (6MB vs. 4MB)
Q8400	E5430 L5430 X3330	E5430: Lower TDP (80 vs. 95W), More cache (12MB vs. 4MB) L5430: Lower TDP (50W vs 95W), More cache (12MB vs. 4MB) X3330: Same TDP, More cache (6MB vs. 4MB)
Q8400S	E5430 L5430 X3330	E5430: Higher TDP (80 vs. 65W), More cache (12MB vs. 4MB) L5430: Lower TDP (50W vs. 65W), More cache (12MB vs. 4MB) X3330: Higher TDP (95W vs. 65W), More cache (6MB vs. 4MB)
Q9300	E5420 L5420 X3320	E5420: Lower TDP (80 vs. 95W), More cache (12MB vs. 6MB) L5420: Lower TDP (50W vs 95W), More cache (12MB vs. 6MB) X3320: No difference. Basically a Q9300 under a different name
Q9400	E5430 L5430 X3330 X3350	E5430: Lower TDP (80 vs. 95W), More cache (12MB vs. 6MB) L5430: Lower TDP (50W vs 95W), More cache (12MB vs. 6MB) X3330: No difference. Basically a Q9400 under a different name X3350: More cache (12MB vs. 6MB)
Q9400S	E5430 L5430 X3330 X3350	E5430: Higher TDP (80 vs. 65W), More cache (12MB vs. 6MB) L5430: Lower TDP (50W vs. 65W), More cache (12MB vs. 6MB) X3330: Higher TDP (95 vs. 65W) X3350: Higher TDP (95 vs. 65W), More cache (12MB vs. 6MB)
Q9500	E5440 L3360 X3360	E5440: Lower TDP (80 vs. 95W), More cache (12MB vs. 6MB) L3360: Lower TDP (65 vs. 95W), More cache (12MB vs. 6MB) X3360: More cache (12MB vs. 6MB)
Q9505	E5440 L3360 X3360	E5440: Lower TDP (80 vs. 95W), More cache (12MB vs. 6MB) L3360: Lower TDP (65 vs. 95W), More cache (12MB vs. 6MB) X3360: More cache (12MB vs. 6MB)
Q9505S	E5440 L3360 X3360	E5440: Higher TDP (80 vs. 65W), More cache (12MB vs. 6MB) L3360: More cache (12MB vs. 6MB) X3360: Higher TDP (95 vs. 65W), More cache (12MB vs. 6MB)
Q9550	E5440 L3360 X3360	E5440: Lower TDP (80 vs. 95W) L3360: Lower TDP (65 vs. 95W) X3360: No difference. Basically a Q9550 under a different name
Q9550S	E5440 L3360 X3360	E5440: Higher TDP (80 vs. 65W) L3360: No difference. Basically a Q9550S under a different name X3360: Higher TDP (95 vs. 65W)
Q9650	E5450 X5450	E5450: Lower TDP (80 vs. 95W) X5450: Higher TDP (120 vs. 95W)
QX9650	E5450 X5450	E5450: Lower TDP (80 vs. 130W), locked multiplier X5450: Lower TDP (120 vs. 130W), locked multiplier
QX9770	X5482 QX9775	X5482: Higher TDP (150 vs. 136W), locked multiplier QX9775: Not really a Xeon but it uses socket LGA771 and is a rebranded X5482 with unlocked multiplier, or a QX9770 under a different name, socket, and TDP rating.
QX9775	X5482	Basically a QX9775 with a locked multiplier.

Exact same Core 2 Quad/Xeons only

Model	Is the same as...
Q9300	X3320
Q9400	X3330
Q9550	X3360
Q9550S	L3360

Xeon overclocking table

Model	FSB speed	Multiplier	Clock	400MHz FSB clock	500MHz FSB clock
E5405	333	6	2.0	2.4	3.0
L5408	266	8	2.13	3.2	4.0
E5410	333	7	2.33	2.8	3.5
L5410	333	7	2.33	2.8	3.5
E5420	333	7.5	2.5	3.0	3.75
L5420	333	7.5	2.5	3.0	3.75
E5430	333	8	2.66	3.2	4.0
L5430	333	8	2.66	3.2	4.0
E5440	333	8.5	2.83	3.4	4.25
E5450	333	9	3.0	3.6	4.5
X5450	333	9	3.0	3.6	4.5
X5460	333	9.5	3.16	3.8	4.75
E5462	400	7	2.8	2.8	3.5
X5470	333	10	3.33	4.0	5.0
X5472	400	7.5	3.0	3.0	3.75
X5482	400	8	3.2	3.2	4.0
X5492	400	8.5	3.4	3.4	4.25