我想换块CPU，请问有几种选择。。主板是 华硕 M3A78(ATI RX780⼀RX790芯片组)

到华硕官方网站查询的你的主板支持的规格
Athlon 64 3000+ (CN),512K,rev.F2,62W,SocketAM2 ALL
0401
Athlon 64 3500+ (DE),512K,rev.G,45W,SocketAM2 ALL
0401
Athlon 64 3800+ (DH),512K,rev.F3,62W,SocketAM2 ALL
0401
Athlon 64 FX-62 (CS),1MBx2,rev.F2,125W,SocketAM2 ALL
0401
Athlon 64 LE-1600+ (DH),1M,rev.F3,45W,SocketAM2 ALL
0401
Athlon 64 LE-1620+ (DH),1M,rev.F3,45W,SocketAM2 ALL
0401
Athlon 64 LE-1640+ (DP),512K,rev.G2,45W,SocketAM2 ALL
0401
Athlon 64 X2 3600+ (DD),1MB,65W,rev.G,SocketAM2 ALL
0401
Athlon 64 X2 3800+ (CZ),512Kx2,65W,rev.F3,SocketAM2 ALL
0401
Athlon 64 X2 4000+ (DD),1MB,rev.G,65W,SocketAM2 ALL
0401
Athlon 64 X2 4200+ (DO),512Kx2,rev.G2,65W,SocketAM2 ALL
0401
Athlon 64 X2 4400+ (DO),1MB,rev.G2,65W,SocketAM2 ALL
0401
Athlon 64 X2 4400+ (DU),1MB,rev.G2,65W,SocketAM2,ADO4400IAA5DU ALL
0602
Athlon 64 X2 4600+ (CU),512Kx2,rev.F2,65W,SocketAM2 ALL
0401
Athlon 64 X2 4800+ (CS),1MBx2,rev.F2,65W,SocketAM2 ALL
0401
Athlon 64 X2 4800+ (DO),1MB,rev.G2,65W,SocketAM2 ALL
0401
Athlon 64 X2 5000+ (DO),1MB,rev.G2,65W,SocketAM2 ALL
0401
Athlon 64 X2 5200+ (CZ),2MB,rev.F3,89W,SocketAM2 ALL
0401
Athlon 64 X2 5400+ (DO),1M,rev.G2,65W,SocketAM2 ALL
0401
Athlon 64 X2 5400+ (DS),1M,rev.G2,65W,SocketAM2 ALL
0401
Athlon 64 X2 5600+ (CZ),2MB,rev.F3,89W,SocketAM2 ALL
0401
Athlon 64 X2 6000+ (CZ),2MB,rev.F3,125W,SocketAM2 ALL
0401
Athlon 64 X2 6000+ (DO),1MB,rev.G2,89W,SocketAM2 ALL
0602
Athlon 64 X2 6400+ (CZ),2MB,rev.F3,125W,SocketAM2 ALL
0401
Athlon 64 X2 6500+ ,2.3GHz,1MB,rev.B3,AD6500WCJ2BGH,95W,SocketAM2 ALL
0602
Athlon IIX4 600e(AD600EHDK42GI),2.2GHz,512KB,rev.C2,45W,SocketAM3 1.00G
1301
Athlon IIX4 605e(AD605EHDK42GI),2.3GHz,512KB,rev.C2,45W,SocketAM3 1.00G
1301
Athlon IIX4 620(ADX620WFK42GI),2.6GHz,512KB,rev.C2,95W,SocketAM3 ALL
1802
Athlon IIX4 630(ADX630WFK42GI),2.8GHz,512KB,rev.C3,95W,SocketAM3 ALL
1802
Athlon X2 5000+ (DU),1MB,rev.G2,65W,SocketAM2 ALL
0602
Athlon X2 5050e (DO),1MB,rev.G2,45W,ADH5050IAA5DO,SocketAM2 ALL
0702
Athlon X2 7450+ ,2.4GHz,2MB,rev.B3,AD7450WCJ2BGH,95W,SocketAM2+ ALL
0804
Athlon X2 7550+ ,2.5GHz,2MB,rev.B3,AD7550WCJ2BGH,95W,SocketAM2+ ALL
0804
Athlon X2 7750+ ,2.7GHz,2MB,rev.B3,AD7750WCJ2BGH,95W,SocketAM2+ 1.00G
1001
Athlon X2 7750+ ,2.7GHz,2MB,rev.B3,AD775ZWCJ2BGH,95W,SocketAM2+ ALL
0804
Athlon X2 7850+ ,2.8GHz,2MB,rev.B3,AD785ZWCJ2BGH,95W,SocketAM2+ 1.00G
1001
Athlon X2 BE-2300 (DD),1M,45W,rev.G1,SocketAM2 ALL
0401
Athlon X2 BE-2350 (DO),1M,45W,rev.G2,SocketAM2 ALL
0401
Athlon X2 BE-2400 (DO),1M,45W,rev.G2,SocketAM2 ALL
0401
Phenom IIX2 545 (HDX545WFK2DGI),3.0GHz,80W,rev.C2,SocketAM3,Dual-Core ALL
1606
Phenom IIX2 550 (HDZ550WFK2DGI),3.1GHz,80W,rev.C2,SocketAM3,Dual-Core ALL
1606
Phenom IIX3 710 (HDX710WFK3DGI),2.6GHz,95W,rev.C2,SocketAM3,Triple-Core ALL
1001
Phenom IIX3 720 (HDZ720WFK3DGI),2.8GHz,95W,rev.C2,SocketAM3,Triple-Core ALL
1001
Phenom IIX4 805 (HDX805WFK4FGI),2.5GHz,95W,rev.C2,SocketAM3,Quad-Core ALL
1001
Phenom IIX4 810 (HDX810WFK4FGI),2.6GHz,95W,rev.C2,SocketAM3,Quad-Core ALL
0804
Phenom IIX4 910 (HDX910WFK4DGI),2.6GHz,95W,rev.C2,SocketAM3,Quad-Core ALL
1001
Phenom IIX4 920 (HDX920XCJ4DGI),2.8GHz,125W,rev.C2,SocketAM2+,Quad-Core ALL
0804
Phenom IIX4 925 (HDX925WFK4DGI),2.8GHz,95W,rev.C2,SocketAM3,Quad-Core ALL
0804
Phenom IIX4 940 (HDZ940XCJ4DGI),3.0GHz,125W,rev.C2,SocketAM2+,Quad-Core ALL
0804
Phenom IIX4 945 (HDX945FBK4DGI),3.0GHz,125W,rev.C2,SocketAM3,Quad-Core ALL
1301
Phenom IIX4 955 (HDZ955FBK4DGI),3.2GHz,125W,rev.C2,SocketAM3,Quad-Core ALL
1301
Phenom X3 8250e (HD8250ODJ3BGH),1.9GHz,rev.B3,65W,SocketAM2+,Triple-Core ALL
0401
Phenom X3 8400 (HD8400WCJ3BGD),2.1GHz,rev.B2,95W,SocketAM2+,Triple-Core ALL
0401
Phenom X3 8450 (HD8450WCJ3BGH),2.1GHz,rev.B3,95W,SocketAM2+,Triple-Core ALL
0401
Phenom X3 8450e (HD8450ODJ3BGH),2.1GHz,rev.B3,65W,SocketAM2+,Triple-Core ALL
0401
Phenom X3 8550 (HD8550WCJ3BGH),2.2GHz,rev.B3,95W,SocketAM2+,Triple-Core ALL
0401
Phenom X3 8600(HD8600WCJ3BGD),2.3GHz,95W,rev.B2,SocketAM2+,Triple-Core ALL
0401
Phenom X3 8650 (HD8650WCJ3BGH),2.3GHz,95W,rev.B3,SocketAM2+,Triple-Core ALL
0703
Phenom X3 8750 (HD8750WCJ3BGH),2.4GHz,rev.B3,95W,SocketAM2+,Triple-Core ALL
0703
Phenom X3 8750 (HD875ZWCJ3BGH),2.4GHz,rev.B3,95W,SocketAM2+,Triple-Core ALL
0602
Phenom X3 8850 (HD8850WCJ3BGH),2.4GHz,rev.B3,95W,SocketAM2+,Triple-Core ALL
0702
Phenom X4 9100e (HD910OBJ4BGD),1.8GHz,65W,rev.B2,SocketAM2+,Quad-Core ALL
0401
Phenom X4 9150 (HD9150ODJ4BGH),1.8GHz,65W,rev.B3,SocketAM2+,Quad-Core ALL
0602
Phenom X4 9150e (HD9150ODGHBOX),1.8GHz,65W,rev.B3,SocketAM2+,Quad-Core ALL
0703
Phenom X4 9350 (HD9350ODJ4BGH),2.0GHz,65W,rev.B3,SocketAM2+,Quad-Core ALL
0602
Phenom X4 9450e (HD9450ODJ4BGH),2.1GHz,65W,rev.B3,SocketAM2+,Quad-Core ALL
0703
Phenom X4 9500 (HD9500WCJ4BGD),2.2GHz,rev.B2,95W,SocketAM2+,Quad-Core ALL
0401
Phenom X4 9550 (HD9550WCJ4BGH),2.2GHz,rev.B3,95W,SocketAM2+,Quad-Core ALL
0703
Phenom X4 9600 (HD9600WCJ4BGD),2.3GHz,95W,rev.B2,SocketAM2+,Quad-Core ALL
0401
Phenom X4 9600 (HD960ZWCJ4BGD),2.3GHz,95W,rev.B2,SocketAM2+,Quad-Core ALL
0703
Phenom X4 9650 (HD9650WCJ4BGH),2.3GHz,95W,rev.B3,SocketAM2+,Quad-Core ALL
0703
Phenom X4 9750 (HD9750WCJ4BGH),2.4GHz,95W,rev.B3,SocketAM2+,Quad-Core ALL
0703
Phenom X4 9750 (HD9750XAJ4BGH),2.4GHz,125W,rev.B3,SocketAM2+,Quad-Core ALL
0703
Phenom X4 9850 (HD9850WCJ4BGH,rev.B3,SocketAM2+,Quad-Core ALL
0703
Phenom X4 9850 (HD9850XAJ4BGH),2.5GHz,125W,rev.B3,SocketAM2+,Quad-Core ALL
0703
Phenom X4 9850 (HD985ZXAJ4BGH),2.5GHz,125W,rev.B3,SocketAM2+,Quad-Core ALL
0703
Phenom X4 9950 (HD995ZXAJ4BGH),2.6GHz,125W,rev.B3,SocketAM2+,Quad-Core ALL
0602
Sempron 2100+ (DD),512K,rev.G1,65W,SocketAM2 ALL
0401
Sempron 2100+ (DO),512K,rev.G2,65W,SocketAM2 ALL
0401
Sempron 2800+ (CN),128K,rev.F2,62W,SocketAM2 ALL
0401
Sempron 3200+ (CN),128K,rev.F2,62W,SocketAM2 ALL
0401
Sempron 3600+ (CW),256K,rev.F2,62W,SocketAM2 ALL
0401
Sempron 3800+ (CN),256K,rev.F2,62W,SocketAM2 ALL
0401
Sempron LE-1100 (DE),256K,rev.G1,45W,SocketAM2 ALL
0401
Sempron LE-1150 (DE),256K,rev.G1,45W,SocketAM2 ALL
0401
Sempron LE-1200 (DE),512K,rev.G2,45W,SocketAM2 ALL
0401
Sempron LE-1200 (DP),512K,rev.G2,45W,SocketAM2 ALL
0702
Sempron LE-1300 (DP),512K,rev.G2,45W,SocketAM2 ALL
0401
这是网址http://www.asus.com.cn/product.aspx?P_ID=5pvgDAXJUV2orYzn

Phenom X3 8650为三核CPU，性能已经够强悍了，假如这也满足不了你的要求，那只能上四核的U了！

你的主板是Socket AM2/AM2+ 的cpu插槽。所以现在新出的U都不能用了，现在的U都是AM3接口的了。现在市面上可能还有少量的AMD Phenom X3 8750 或者AMD Athlon X2 5000+。但是你的8650跟这两个U性能差不多，所以你换U也提升不了性能了，除非你用AMD Athlon X2 5000开核用。

AMD平台没啥必要。。。加内存倒是可以提高性能.加硬盘也可以，毕竟这都是看的剑的东西。