Imagination Technologies was topping the leaderboard on Tuesday. The previous day the group announced details of a new chip, based on its version of the MIPS Series 5 architecture. The news has impressed investors because the technology is able to challenge competitors such as ARM. Satellite and cable technology firm Pace was rising strongly for the second straight day after Bloomberg reported that Netflix is in talks to add TV subscription-streaming services to set-top boxes of US cable-TV operators.Builder Bellway also rose after lifting its final dividend 50%, buoyed by exceptional prospects for the UK housing market and a bulging order book.Meanwhile, Oxford Instruments shares suffered following a downgrade by Goldman Sachs. FTSE 250 - RisersImagination Technologies Group (IMG) 288.50p +5.52%Rightmove (RMV) 2,528.00p +4.94%Man Group (EMG) 82.35p +4.64%Senior (SNR) 263.20p +4.07%Bellway (BWY) 1,442.00p +4.04%Pace (PIC) 284.70p +3.72%Ferrexpo (FXPO) 191.80p +3.68%Kazakhmys (KAZ) 263.10p +3.10%CSR (CSR) 533.00p +3.09%BlackRock World Mining Trust (BRWM) 484.90p +2.60%FTSE 250 - FallersOxford Instruments (OXIG) 1,355.00p -3.35%Ladbrokes (LAD) 186.10p -2.87%Edinburgh Inv Trust (EDIN) 586.00p -2.74%Renishaw (RSW) 1,700.00p -2.30%Homeserve (HSV) 248.80p -2.05%Spirent Communications (SPT) 127.00p -1.93%Polymetal International (POLY) 549.00p -1.88%Menzies(John) (MNZS) 812.00p -1.87%Carpetright (CPR) 650.50p -1.81%PZ Cussons (PZC) 400.50p -1.81%NR