Chip designer ARM Holdings was the best performing stock on Wednesday, helped by some positive comment from the broker ING, which expects ARM to meet its guidance. Household products giant Reckitt Benckiser was also a big mover, boosted by JP Morgan who upped its earnings per share estimates by 3% saying that a current weak share price provides a good buying opportunity. Mexican miner Fresnillo's silver production slipped slightly in the quarter to 31 March, but expanded capacity at its Soledad-Dipolos mine helped lift gold production by 13.3% to 96,407 ounces. Fresnillo's chief executive Jaime Lomelin said the company is on track to produce 44m ounces of silver over 2011. Shares were 1% higher.Meanwhile, sector peers Lonmin and Anglo American were heading the other way.FTSE 100 - RisersARM Holdings (ARM) 598.00p +6.79%Reckitt Benckiser Group (RB.) 3,366.00p +4.21%GKN (GKN) 203.50p +3.51%G4S (GFS) 268.60p +2.79%Sage Group (SGE) 275.40p +2.65%Burberry Group (BRBY) 1,160.00p +2.47%Next (NXT) 2,149.00p +2.43%Hargreaves Lansdown (HL.) 621.00p +2.22%National Grid (NG.) 599.00p +2.22%Serco Group (SRP) 554.00p +2.21%FTSE 100 - FallersOld Mutual (OML) 138.60p -4.28%Lonmin (LMI) 1,649.00p -2.31%Carnival (CCL) 2,436.00p -1.62%IMI (IMI) 995.00p -1.58%Anglo American (AAL) 3,146.50p -1.27%Amec (AMEC) 1,155.00p -1.20%Capita Group (CPI) 707.50p -0.98%Petrofac Ltd. (PFC) 1,514.00p -0.85%Investec (INVP) 481.90p -0.74%Kazakhmys (KAZ) 1,409.00p -0.70%