Loading more than 1GB PCAP file

Use the command line tool editcap to slice it up.

Given the size of the capture, I guess that you don't want to study every packet details.

• If you want to study a specific flow inside this haystack, you can try to narrow down the size of the file to load by filtering out unneeded traffic with tcpdump or tshark (check -r and -w options, plus a "good" filter).
• If you want to have statistics over the whole capture, you may try using tshark - the command line tool - instead of wireshark. It may require less memory as it does not have a graphical UI. Statistics are related to the -z option. For example tshark -z rtp,streams -r sip-rtp-g711a.pcap -q gives information about RTP streams without printing a summary line per packet.