AMD sempron 145 NB and HTlink frequency issue

I have a sempron 145 cpu.i managed to overclock it upto 3.5ghz with full stability on stock voltage.it is achieved by fsb of 250 and multi of x14,nb was at 2000mhz with multi of 8x and htlink was at 2000mhz by same 8x multi.i felt my system was noticeble fast but i want more fast .so first i change multi of Nb to 10x to make cpu-nb frequency higher and Htlink to 9x to keep system stable and now they were at 2500 and 2250 so still system was at 3.5ghz but i notice that my system was a bit slower.when Nb and Htlink both were at near their stock frequency system was faster then now.so help me to understand that"does higher NB and HTlink make system slower then their stock frequency".

There is really not an answer that you can prove by normal testing. Sometimes I have seen AMD systems perform better with the HT even underclocked. Not often but sometimes. In your case a marginal system when pushed could be causing the cpu into error correcting some data and slowing the overall performance. Increasing the CPU/NB voltage might return full stability if that is what is at issue.

I have done some test of my cpu and i found higher nb and htlink frequency increased my 3d performance upto 15% but discrease my cpu performance a bit.so if you keep your nb and htlink frequency to near their stock this will increase your cpu performance but does not effect 3d performance.just like unlocked multi cpu's. in those cpu incresment in multi will increase cpu speed as well as performance but does not gain 3d performance because it does not increase nb and htlink.

I would try leaving the HT Link at stock frequency while overclocking the CPUNB as you have done. It is pretty well known that overclocking the HT Link does not improve performance and can even degrade performance. While overclocking the HT Link does not improve performance it can enhance stability on some AMD CPU lines, most notably the Thuban Core Phenom IIs and BD and PD lines as well I think.