Loop problem urgent (rewards....)

Hiii my program is giving a timt out error in the above loop.

LOOP AT IBSID2.(consist of 85000 records)

LOOP AT IBSID1(consist of 85000 records) WHERE KUNNR EQ IBSID2-KUNNR.

V_TABIX2 = SY-TABIX.

IF SY-SUBRC EQ 0.

IBSID2-TOT_30 = IBSID1-AGE30 + IBSID1-AGE30C .

IBSID2-TOT_60 = IBSID1-AGE60 + IBSID1-AGE60C .

IBSID2-TOT_180 = IBSID1-AGE180 + IBSID1-AGE180C .

IBSID2-TOT_360 = IBSID1-AGE360 + IBSID1-AGE360C .

IBSID2-TOT_360M = IBSID1-AGE360M + IBSID1-AGE360MC .

IBSID2-TOT_OUT_INCL = IBSID1-R_DMBTR + IBSID1-SPGLAMT +

IBSID1-SPGLAMTD.

ENDIF.

MODIFY IBSID2 INDEX V_TABIX2 TRANSPORTING TOT_30 TOT_60

TOT_180 TOT_360 TOT_360M TOT_OUT_INCL.

CLEAR IBSID2.

ENDLOOP.

ENDLOOP.

so what is alternate to this problem i tried instead of loop at ibsid1 i tried

read table ibsid1 with key kunnr = ibsid2-kunnr. but some values r not coming properly..

thanking you..

Rewards point for correct ans.