Light alternative to LibreOffice to work with libre formats and Microsoft Office proprietary formats?

I installed LibreOffice long time before but its resources consumption is too much for a computer with only 256 MB RAM (Microsoft Office 2003 uses 32 MB RAM while LibreOffice uses 100 MB to 200 MB –without using databases support nor Java-).

If somebody knows other programs group or office suite which can be used to work with ODF libre formats and proprietary formats from MS Office Word, MS Office Excel and MS Office PowerPoint: .doc .docx .xls .xlsx .ppt and pptx, publishes it here.

Thanks.

->Same forum topic in Spanish:
https://trisquel.info/es/forum/%C2%BFuna-alternativa-ligera-libreoffice-para-trabajar-con-formatos-libres-y-formatos-de-microsoft-